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A volcano is a feature in Earth's crust where molten rock is squeezed out onto the Earth's surface. This molten rock is called magma when it is beneath the surface and lava when it erupts, or flows out, from a volcano. Along with lava, volcanoes also release gases, ash, and solid rock. Volcanoes come in many different shapes and sizes but are most commonly cone-shaped hills or mountains. They are found throughout the world, forming ridges deep below the sea surface and mountains that are thousands of meters high. About 1,900 volcanoes on Earth are considered active, meaning they show some level of occasional activity and are likely to erupt again. Many others are dormant volcanoes, showing no current signs of exploding but likely to become active at some point in the future. Others are considered extinct. Volcanoes are incredibly powerful agents of change. Eruptions can create new landforms, but can also destroy everything in their path. About 350 million people (or about one out of every 20 people in the world) live within the "danger range" of an active volcano. Volcanologists closely monitor volcanoes so they can better predict impending eruptions and prepare nearby populations for potential volcanic hazards that could endanger their safety. Plate Tectonics Most volcanoes form at the boundaries of Earth's tectonic plates. These plates are huge slabs of the Earth's crust and upper mantle, which fit together like pieces of a puzzle. These plates are not fixed, but are constantly moving at a very slow rate. They move only a few centimeters per year. Sometimes, the plates collide with one another or move apart. Volcanoes are most common in these geologically active boundaries. The two types of plate boundaries that are most likely to produce volcanic activity are divergent plate boundaries and convergent plate boundaries. Divergent Plate Boundaries At a divergent boundary, tectonic plates move apart from one another. They never really separate because magma continuously moves up from the mantle into this boundary, building new plate material on both sides of the plate boundary. The Atlantic Ocean is home to a divergent plate boundary, a place called the Mid-Atlantic Ridge. Here, the North American and Eurasian tectonic plates are moving in opposite directions. Along the Mid-Atlantic Ridge, hot magma swells upward and becomes part of the North American and Eurasian plates. The upward movement and eventual cooling of this buoyant magma creates high ridges on the ocean floor. These ridges are interconnected, forming a continuous volcanic mountain range nearly 60,000 kilometers (37,000 miles)-the longest in the world. Another divergent plate boundary is the East Pacific Rise, which separates the massive Pacific plate from the Nazca, Cocos, and North American plates. Vents and fractures (also called fissures) in these mid-ocean ridges allow magma and gases to escape into the ocean. This submarine volcanic activity accounts for roughly 75% of the average annual volume of magma that reaches the Earth's crust. Most submarine volcanoes are found on ridges thousands of meters below the ocean surface. Some ocean ridges reach the ocean surface and create landforms. The island of Iceland is a part of the Mid-Atlantic Ridge. The diverging Eurasian and North American plates caused the eruptions of Eyjafjallajökull (in 2010) and Bardarbunga (in 2014). These eruptions were preceded by significant rifting and cracking on the ground surface, which are also emblematic of diverging plate movement. Of course, divergent plate boundaries also exist on land. The East African Rift is an example of a single tectonic plate being ripped in two. Along the Horn of Africa, the African plate is tearing itself into what is sometimes called the Nubian plate (to the west, including most of the current African plate) and the Somali plate (to the east, including the Horn of Africa and the western Indian Ocean). Along this divergent plate boundary are volcanoes such as Mount Nyiragongo, in the Democratic Republic of Congo, and Mount Kilimanjaro, in Kenya. Convergent Plate BoundariesAt a convergent plate boundary, tectonic plates move toward one another and collide. Oftentimes, this collision forces the denser plate edge to subduct, or sink beneath the plate edge that is less dense. These subduction zones can create deep trenches. As the denser plate edge moves downward, the pressure and temperature surrounding it increases, which causes changes to the plate that melt the mantle above, and the melted rock rises through the plate, sometimes reaching its surface as part of a volcano. Over millions of years, the rising magma can create a series of volcanoes known as a volcanic arc. The majority of volcanic arcs can be found in the Ring of Fire, a horseshoe-shaped string of about 425 volcanoes that edges the Pacific Ocean. If you were to drain the water out of the Pacific Ocean, you would see a series of deep canyons (trenches) running parallel to corresponding volcanic islands and mountain ranges. The Aleutian Islands, stretching from Alaska to Russia in the Bering Sea, for instance, run parallel to the Aleutian Trench, formed as the Pacific plate subducts under the North American plate. The Aleutian Islands have 27 of the United States' 65 historically active volcanoes. The mighty Andes Mountains of South America run parallel to the Peru-Chile Trench. These mountains are continually built up as the Nazca plate subducts under the South American plate. The Andes Mountains include the world's highest active volcano, Nevados Ojos del Salado, which rises to 6,879 meters (over 22,500 feet) along the Chile-Argentina border. For many years, scientists have been trying to explain why some volcanoes exist thousands of kilometers away from tectonic plate boundaries. The dominant theory, framed by Canadian geophysicist J. Tuzo Wilson in 1963, states that these volcanoes are created by exceptionally hot areas fixed deep below Earth's mantle. These hot spots are able to independently melt the tectonic plate above them, creating magma that erupts onto the top of the plate. In hot spots beneath the ocean, the tectonic activity creates a volcanic mound. Over millions of years, volcanic mounds can grow until they reach sea level and create a volcanic island. The volcanic island moves as part of its tectonic plate. The hot spot stays put, however. As the volcano moves farther from the hot spot, it goes extinct and eventually erodes back into the ocean. A new and active volcano develops over the hot spot, creating a continuous cycle of volcanism-and a string of volcanic islands tracing the tectonic plate's movement over time. For Wilson and many scientists, the best example of hot spot volcanism is the Hawaiian Islands. Experts think this volcanic chain of islands has been forming for at least 70 million years over a hot spot underneath the Pacific plate. Of all the inhabited Hawaiian Islands, Kauai is located farthest from the presumed hot spot and has the most eroded and oldest volcanic rocks, dated at 5.5 million years. Meanwhile, on the "Big Island" of Hawaii-still fueled by the hot spot-the oldest rocks are less than 0.7 million years old and volcanic activity continues to create new land. Hot spots can also create terrestrial volcanoes. The Yellowstone Supervolcano, for instance, sits over a hot spot in the middle of the North American plate, with a series of ancient calderas stretching across southern Idaho. The Yellowstone hot spot fuels the geysers, hot springs, and other geologic activity at Yellowstone National Park, Wyoming. While some data seem to prove Wilson's hot spot theory, more recent scientific studies suggest that these hot spots may be found at more shallow depths in the Earth's mantle and may migrate slowly over geologic time rather than stay fixed in the same spot. Principal Types of Volcanoes While volcanoes come in a variety of shapes and sizes, they all share a few key characteristics. All volcanoes are connected to a reservoir of molten rock, called a magma chamber, below the surface of the Earth. When pressure inside the chamber builds up, the buoyant magma travels out a surface vent or series of vents, through a central interior pipe or series of pipes. These eruptions, which vary in size, material, and explosiveness, create different types of volcanoes. Stratovolcanoes Stratovolcanoes are some of the most easily recognizable and imposing volcanoes, with steep, conic peaks rising up to several thousand meters above the landscape. Also known as composite volcanoes, they are made up of layers of lava, volcanic ash, and fragmented rocks. These layers are built up over time as the volcano erupts through a vent or group of vents at the summit's crater. Mount Rainier is an impressive stratovolcano that rises 4,392 meters (14,410 feet) above sea level just south of Seattle, Washington. Over the past half million years, Mount Rainier has produced a series of alternating lava eruptions and debris eruptions. These eruptions have given Mount Rainier the classic layered structure and conic shape of a composite volcano. The volcano's peak has also been carved down by a series of glaciers, giving it a craggy and rugged shape. Volcan de Fuego and Acatenango are a pair of stratovolcanoes that stand more than 3,700 meters (12,000 feet) above sea level near Antigua, Guatemala. While the volcanoes are considered twins because of their similar shape and size, they are made of different types of lava and have distinct eruption histories. While Acatenango erupts infrequently today, Fuego is considered to be the most active volcano in Central America, erupting more than 60 times since 1524. Shield Volcanoes Shield volcanoes are built almost exclusively of lava, which flows out in all directions during an eruption. These flows, made of highly fluid basalt lava, spread over great distances and cool in thin layers. Over time, the layers build up and create a gently sloping dome that looks like a warrior's shield. While they are not as eye-catching as their steep stratovolcano cousins, shield volcanoes are often much larger in volume because of their broad, expansive structure. Shield volcanoes make up the entirety of the Hawaiian Islands. The Kilauea and Mauna Loa shield volcanoes, located on the "Big Island" of Hawaii, rise from the ocean floor more than 4,500 meters (15,000 feet) below sea level. The summit of Mauna Loa stands at 4,168 meters (13,677 feet) above sea level and more than 8,500 meters (28,000 feet) above the ocean floor, making it the world's largest active volcano-and, by some accounts, the world's tallest mountain. The smaller volcano, Kilauea, has been erupting continuously since 1983, making it one of the world's most active volcanoes. The Galapagos Islands are also made up of a series of shield volcanoes. Isabela and Fernandina islands have flatter tops than other shield volcanoes because lava erupts from fissures around their tops and along ridges at their bases. As a result, the volcanoes rise at the top and grow outward at the bottom-but not in the middle, making them look like an "inverted soup bowl." prolific type of volcano on Earth. They can develop as part of stratovolcanoes, shield volcanoes, or independently. Also known as cinder cones, they form after violent eruptions blow lava into the air. In the atmosphere, the lava fragments solidify and fall as "cinders" around a singular vent. Often formed from a single eruption or short series of eruptions, pyroclastic cones only stand at heights of tens of meters to hundreds of meters. Parícutin, Mexico, is a unique pyroclastic cone. It was the first volcano to be studied for its entire life cycle. Emerging from a cornfield in 1943, Parícutin's explosive eruptions caused it to reach 80% of its height of 424 meters (1,391 feet) during its first year of activity. In that time, lava and ash buried the nearby town of San Juan. Over the next eight years, Parícutin built the remainder of its cone-and then went quiet. Geologists learned a great deal about the evolution of volcanoes in Parícutin's short, nine-year life. Lava domes are like shield volcanoes in that they are built entirely of lava. This lava, however, is too thick and sticky to move great distances. It just piles up around the volcano vent. Lava domes are often found on the summit or flanks of a volcano, but they can also develop independently. Like pyroclastic cones, they only reach a few hundred meters, as they are formed during singular eruptions or slow lava releases. One of the most iconic lava domes developed after the devastating 1902 eruption of Mount Pelée on the island of Martinique. For almost a year, a lava dome grew out of a summit crater created from the eruption, reaching a height of more than 300 meters (1,000 feet). Known as the Tower of Pelée, the obelisk-shaped structure was twice the height of the Washington Monument. It ultimately collapsed into a pile of rubble after 11 months of growth. Other Important Volcanic Features CalderasSome volcanoes experience such large, explosive eruptions that they release most of the material in their magma chamber. This causes the land around the erupting vent or vents to collapse inwardly, creating circular depressions called calderas. Depending on their intensity and duration, volcanic eruptions can create calderas as much as 100 kilometers wide. Crater Lake, Oregon, is in a caldera about 10 kilometers (6 miles) wide. Crater Lake's caldera resulted from an eruption that occurred more than 7,000 years ago. The volcano's magma chamber collapsed, then filled with water from rain and snow, creating the lake. Crater Lake is the deepest lake in the United States. Deception Island, located off the coast of Antarctica, experienced a violent eruption roughly 10,000 years ago. The volcano summit collapsed, forming a caldera 7 kilometers (4.4 miles) wide and flooded with seawater. The caldera gives Deception Island its horseshoe shape, which opens to the sea through a narrow channel. Deception Island's unique geologic structure makes it one of the only places in the world where ocean vessels can sail directly into an active volcano. CratersMuch like calderas, craters are depressions left after a volcano experiences a large eruption. While calderas are formed by the collapse of material inside a volcano, craters are formed as materials explode out from a volcano. Craters are usually much smaller than calderas, only extending to a maximum of about one kilometer (.62 mile) in diameter. Many volcanoes have multiple craters caused by different eruptions. The Maly Semiachik volcano, located on the Kamchatka Peninsula in far eastern Russia, has six craters at its summit. The youngest of these craters, Troitsky, filled in with water and snowmelt, creating a lake 140 meters (459 feet) deep. The lake is highly acidic, as volcanic gases continue to be released into the water from the active volcano below. Lava lakes are also found in volcanic craters. Erta Ale, a volcano in Ethiopia, has a lava lake in its summit crater. Lava lakes are where magma has bubbled up to the surface and pooled in a crater. Volcanologists can fly over Erta Ale's summit crater to see how the lava lake is behaving and predict future behavior. Types of Volcanic Eruptions Volcanic eruptions are as diverse as volcanoes themselves-which is to say, very diverse! Some of the ways volcanologists have classified these eruptions are based on the heights they reach, the types of materials they eject, and the explosiveness of these ejections. Hawaiian Hawaiian eruptions are the calmest eruption type. They are characterized by steady lava eruptions known as lava fountains or fire fountains. Lava fountains are able to reach heights of up to 2 kilometers (1.2 miles). The highly fluid lava associated with Hawaiian eruptions flows easily away from the volcano summit, often creating fiery rivers and lakes of lava within depressions on the surrounding landscape. These eruptions are named after the Hawaiian Islands, where they most often occur. Kilauea, which has been erupting continuously since 1983, has produced lava flows covering more than 100 square kilometers (37 square miles) on the island of Hawaii. These flows continuously destroy houses and communities in their path, while also adding new coastline to the island. Strombolian Strombolian eruptions are characterized by short-lived outbursts of lava rather than steady fountaining. The lava is thicker and has a higher gas content than that of Hawaiian eruptions. Large gas bubbles rise from the magma chamber, pushing the pasty lava upward until the bubbles explode at the summit vent. These explosions can reach heights up to 10 kilometers (6.2 miles) although most don't go higher than a few hundred meters into the air. Strombolian eruptions are named after the Mediterranean island of Stromboli, Italy. Considered by many to be the most active volcano on Earth, Stromboli has been erupting almost continuously for 2,000 years. The island's eruptions are almost always Strombolian in nature: Small gas explosions eject blobs of lava into the air a couple of times per hour. VulcanianVulcanian eruptions are short-lived but much more explosive than Strombolian eruptions. Very thick lava causes gas pressure to build up in the magma chamber. When this pressure is finally released it creates canon-like explosions that can travel faster than 350 meters per second (800 miles per hour). Lava, rock, and ash are propelled up to 20 kilometers (12.4 miles) in the air, although most eruption columns are between 5 and 10 kilometers high. These plumes of material have the ability to drift moderate distances away from the eruption site. The 2013 vulcanian eruption of Sakurajima, on the island of Kyushu, Japan, covered the nearby city of Kagoshima in a thick coat of ash. Plinian Reaching as high as 50 kilometers (35 miles) in the atmosphere, Plinian eruptions are the largest of all eruption types. Much like vulcanian eruptions, they eject materials at speeds of hundreds of meters per second. Plinian eruptions, however, are more sustained than the coughing fits of vulcanian eruptions. These consistent eruptions result from the volcano's magma and growing gas bubbles rising at a similar velocity. Plinian eruptions are the most destructive type of eruption. They release a deadly mixture of lava, ash, and volcanic rocks such as scoria and pumice, which can fall kilometers away from the eruption site. They are also characterized by pyroclastic flow, a fluid mixture of fragmented materials and extremely hot, toxic gases. In 79 CE, a series of Plinian eruptions from Mount Vesuvius buried the nearby Roman cities of Pompeii and Herculaneum (in what is today Italy). The cities and their 13,000 inhabitants were buried in volcanic ash and rock. Rainfall mixed with the ash and created a concrete-like substance that preserved the city for thousands of years. SurtseyanSurtseyan eruptions occur where magma or lava interacts with water, most often when an undersea volcano reaches the ocean surface. Another term for this sort of interaction is a phreatomagmatic eruption. When heated rapidly by lava, water flashes to steam and expands violently, creating the most explosive of all eruption types. This aggressive interaction between water and heat is able to fragment lava into very fine grains of ash that can reach heights of 20 kilometers (12.4 miles). Tonga's islands of Hunga Tonga and Hunga Ha'apai are actually the tops of a single, large underwater volcano. In 2009, the volcano erupted for several days, causing steam and ash to explode from the water to altitudes of 5 kilometers (3.1 miles). While the eruptions killed all signs of wildlife on and around the islands, it also added hundreds of square meters of land to Hunga Ha'apai. Volcanic Hazards Volcanoes are some of Earth's most potent natural hazards and agents of change. They release enormous amounts of energy and material, engaging natural processes that can modify landscapes at a local, regional, and even global scale. Many volcanic materials and processes pose a threat to human, animal, and other ecological communities. Volcanic GasVolcanoes regularly release volcanic gases that can be dangerous at concentrated levels. Carbon dioxide and fluorine can collect in soil or volcanic ash, causing crop failure, animal death and deformity, and human illness. Volcanic eruptions can also release massive amounts of sulfur dioxide, which rises into the stratosphere. There, it reflects incoming solar radiation while absorbing outgoing land radiation, leading to a cooling of the Earth's temperature. In extreme cases, these "volcanic winters" can cause crop failures and drastically affect weather. The 1815 eruption of Mount Tambora, Indonesia, cooled the average global temperature by as much as 3° Celsius (5.4° Fahrenheit), causing the "year without a summer." The enormous energy of volcanic eruptions can cause large landslides that move at speeds of more than 100 kilometers per hour (60 miles per hour). Mount St. Helens, Washington, is a stratovolcano that had an explosive Plinian eruption in 1980. The eruption produced the largest landslide in recorded history, covering a 36-kilometer (14-mile) area of land with ash and rocks. Reaching speeds of 50 to 80 meters (165 to 260 feet) per second, the landslide had enough power to surge over a ridge 400 meters (1,312 feet) high. Landslides can mix with surrounding rivers, ice, snow, or rain to produce watery mixtures called lahars. This mixture of water, rock, and debris creates a sludge that can obliterate almost anything in its path. The 1985 eruption of Nevado del Ruiz, Colombia, caused small lahars of rock, ash, and melted snow to flow down into the surrounding river valleys. The lahars gained momentum and size as they traveled the riverbeds, ultimately destroying more than 5,000 homes and killing more than 23,000 people. Pyroclastic FlowsExplosive eruptions sometimes produce pyroclastic flows, a mixture of hot rock fragments and toxic gases that move almost like a liquid out and away from the volcano. Reaching speeds greater than 80 kilometers per hour (50 miles per hour) and temperatures between 200-700° Celsius (392-1292° Fahrenheit), pyroclastic flows knock down, shatter, bury, or burn anything in their path. Pyroclastic flows are responsible for the haunting figures from Pompeii and Herculaneum, Italy. While many scientists thought residents of Pompeii suffocated to death from volcanic gases released during Mount Vesuvius' eruption in 79 CE, new studies suggest that they actually died from extreme heat produced by the volcano's pyroclastic flow. Volcanologist Giuseppe Mastrolorenzo and the Italian National Institute for Geophysics and Volcanology recently discovered that the pyroclastic flow that reached Pompeii produced temperatures of up to 300° Celsius (570° Fahrenheit). These extreme temperatures are able to kill people in a fraction of a second, causing them to spasm in contorted postures like those found amongst the plaster Pyroclastic ConesPyroclastic cones are the most casts of Vesuvius' victims. Volcanic Ash Huge plumes of volcanic ash can spread over large areas of the sky, turning daylight into complete darkness and inhibiting air traffic. (During the eruption of Iceland's Eyjafjallajökull in 2011, flights to and from northern Europe were suspended for more than a week.) Volcanic ash conducts electricity when wet and can contain concentrated levels of toxic materials, posing threats to humans that come in close contact with it on land. The 1994 double eruption of Vulcan and Tavurvur in Papua New Guinea covered the nearby city of Rabaul in a layer of ash up to 75 centimeters (about 2 feet) deep. Rains turned the ash into a cement-like substance that was heavy enough to collapse 80% of the buildings in the city. Volcanic Monitoring and Research Volcanic hazards can be incredibly dangerous to human life. In the United States alone, 54 volcanoes are a very high or high threat to public safety. By closely monitoring volcanic activity, volcanologists can warn people of impending eruptions. While these warnings are not exact predictions, they do provide communities with the valuable time they need to protect themselves against volcanic hazards and ensure their safety. Volcanologists predict volcanic activity by taking real-time measurements and comparing them against what happened in the past. They use a variety of instruments and technologies to monitor temperatures, gas emissions, water levels, ground movements, and changes in the landscape. These measurements paint a clear portrait of a volcano's current state, which volcanologists then interpret against historical data. Volcanologists issue eruption warnings when these measurements stray far from the norm or mirror those that preceded a historic eruption. Different countries use different systems to issue eruption warnings to the public. All of these systems categorize their alerts based on the probability and severity of an impending eruption. Typical volcanic behavior is often represented by the number 1 or the color green, while an imminent and potentially destructive eruption is typically represented by the number 4 or the color red. A number of international organizations lead the way in volcanic monitoring and research, providing invaluable information to scientists, volcanologists, and the public alike. The Smithsonian Institution's Global Volcanism Program documents current activity for all the volcanoes on the planet through publicly available data, reports, and images. The program also keeps the world's only archive of volcanic activity from the last 10,000 years. As part of the UN International Decade for Natural Disaster Reduction, the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) created a list of 16 "Decade Volcanoes" to study because of the high risk they pose to public safety. Mount Nyiragongo in Democratic Republic of the Congo, for example, is dangerously close to the city of Goma. Its 2002 eruption killed 50 people and forced roughly 450,000 people to evacuate their communities. The Santa María Volcano, which sits right above the city of Quetzaltenango, Guatemala, has been continuously erupting since 2003. The Decade Volcanoes program has brought together geologists, volcanologists, and government officials to closely study these volcanoes and create risk-mitigation plans for potential eruptions.

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Plate Tectonics and Volcanic Activity | National Geographic Society

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A volcano is a feature in Earth's crust where molten rock is squeezed out onto the Earth's surface. This molten rock is called magma when it is beneath the surface and lava when it erupts, or flows out, from a volcano. Along with lava, volcanoes also release gases, ash, and solid rock.

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Tornadoes are one of the most violent and powerful types of weather. They consist of a very fast rotating column of air that usually forms a funnel shape. They can be very dangerous as their high speed winds can break apart buildings, knock down trees, and even toss cars into the air.

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Kids learn about tornadoes including how they form, characteristics, types including supercell and waterspout, categories, and fun facts.

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Brush up on wildfires—learn why they spread, how they can be helpful and what you can do to stay safe.

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BrainPOP - Animated Educational Site for Kids - Science, Social Studies, English, Math, Arts & Music, Health, and Technology

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Forest fires are large uncontrolled fires that take place in the forest. Some of the fiercest fires occur in the forest because there is so much fuel (trees) to burn. Forest fires are a type of wildfire. Other types of wildfires include grass fires, brush fires, and hill fires.

Major Causes of Forest Fires

The major cause of forest fires in the United States is human activities. This can be carelessness such as not putting out a campfire or dropping a lit cigarette. It may also be arson, which is setting a fire on purpose and is against the law. Around 80% of forest fires in the United States are caused by humans.

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Kids learn about forest fires including major human and natural causes, how they spread, firefighters, campfire safety, fun facts, and good wildfires.

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Wildfires

What is a wildfire?
A wildfire also known as a wildland fire, forest fire, vegetation fire, grass fire, peat fire, bushfire (in Australia), or hill fire is an uncontrolled fire often occurring in wildland areas, but which can also consume houses or agricultural resources. Wildfires often begin unnoticed, but they spread quickly igniting brush, trees and homes.

What causes a wildfire?

Common causes of wildfires include lightning, human carelessness, arson, volcano eruption, and pyroclastic cloud from active volcano. Heat waves, droughts, and cyclical climate changes such as El Niño can also have a dramatic effect on the risk of wildfires. Although, more than four out of every five wildfires are caused by people.

Where can wildfires occur?
Wildfires can occur anywhere, but are common in the forested areas of the United States and Canada. They are also susceptible in many places around the world, including much of the vegetated areas of Australia as well as in the Western Cape of South Africa. The climates are sufficiently moist to allow the growth of trees, but feature extended dry, hot periods. Fires are particularly prevalent in the summer and fall, and during droughts when fallen branches, leaves, and other material can dry out and become highly flammable. Wildfires are also common in grasslands and scrublands.
What are the Santa Ana winds?

The Santa Ana winds are hot, dry winds that aggravate the fire danger in forests and bush lands. These winds characteristically appear in Southern California and Northern Baja California weather during autumn and early winter. In southern California, under the influence of Santa Ana winds, wildfires can move at tremendous speeds, up to 40 miles in a single day, consuming up to 1,000 acres per hour. Dense clouds of burning embers push ahead of the flames crossing firebreaks without a problem.

What is a fire tornado?

A fire tornado or fire whirl is just a tornado made of fire. It happens when certain conditions (depending on air temperature and currents), acquires a vertical vorticity and forms a whirl, or a tornado-like effect. Fire tornadoes may be whirlwinds separated from the flames, either within the burn area or outside it. A fire tornado can make fires more dangerous.

How do firefighters put out the wildfires?
Firefighters use a tool known as a pulaski. Its a combination of an ax and hoe used to dig a fireline. A fireline is a strip of land from which all brush and debris have been cleared to rob a wildfire of its fuel. Firefighters also use hotshots and smoke jumpers to clear a large path in a big circle around the fire so the blaze is contained in a ring of dirt. When the fire reaches this area, it runs out of fuel and starves to death. If the fire is too large, however, planes and helicopters fly overhead, dropping water and special chemicals that smother the flames. This pink, fire-retardant chemical is called sky jell-o.

Click Here to get the latest wildfire information.

Click Here for to get more wildfire information.

Click Here to see if there has been any recent wildfire activity across the U.S.

Know the Lingo

SURFACE FIRES - The most common type of wildfires, surface fires move slowly and burn along the forest floor, killing and damaging vegetation.

GROUND FIRES - These are usually started by lightning, ground fires burn on or below the forest floor through the root system.

CROWN FIRES - These fires spread by wind moving quickly along the tops of trees.

SANTA ANA WINDS - "Santa Ana" is the name given to the gusty northeast or east wind that occurs in Southern California during the fall and winter months. Santa Ana winds are often hot and very dry, greatly aggravating the fire danger in forests and bush lands.

CONFLAGRATION - A large and destructive fire, typically aggravated by strong winds that carry firebrands over natural or artificial barriers.

Click Here to learn about more wildfire facts!

Wildfire Safety Tips
BEFORE A WILDFIRE: Have a disaster plan. Know whether you're in a wildfire prone area. Plant fire resistant shrubs and trees around your home. Have a garden hose that is long enough to reach around your home. Prepare a disaster supplies kit for your home and car. Include a first aid kit, canned food and a can opener, bottled water, battery-operated radio, flashlight, protective clothing and written instructions on how to turn off electricity, gas, and water. Always listen to the radio and television for the latest information and instructions for your area.
DURING A WILDFIRE: If you're advised to evacuate then do so immediately. Wear protective clothing and lock your home. Tell someone you left and where you are going. Choose a safe route away from fire hazards. Watch for changes in the speed and direction of fire and smoke.

AFTER A WILDFIRE: Stay away from wildfire areas until it is safe.
Wildfire Activities
Lesson Plan: Here is a great lesson plan on teaching students to have an escape plan if a fire threatens their home.

Science Fair Project Ideas: Here is a complete list of science fair project ideas. Discover the science behind the weather that impacts us every day.

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Weather Wiz Kids weather information for kids

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Weather Wiz Kids is a fun and safe website for kids about all the weather info they need to know. It contains tools for weather education, including weather games, activities, experiments, photos, a glossary and educational teaching materials for the classroom.

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Instantly access Danger! Volcanoes plus over 40,000 of the best books & videos for kids.

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Instantly access over 40,000 of the best books & videos for kids on Epic

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Get unlimited access to 40,000 of the best books, audiobooks, videos, & more for kids 12 and under. Try it free.

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Instantly access over 40,000 of the best books & videos for kids on Epic

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Get unlimited access to 40,000 of the best books, audiobooks, videos, & more for kids 12 and under. Try it free.

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Explore National Geographic. A world leader in geography, cartography and exploration.

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Scholastic Teaching Tools | Resources for Teachers

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Explore Scholastic Teaching Tools for teaching resources, printables, book lists, and more. Enhance your classroom experience with expert advice!

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Kids learn about the science of volcanoes including how they form mountains, lava, and magma; types such as cinder cone, composite, and shield; watch a video about volcanoes.

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Kids learn about the science of volcanoes including how they form mountains, lava, and magma; types such as cinder cone, composite, and shield; watch a video about volcanoes.

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Volcanoes
(Volcanoes are not associated with weather, but instead are natural disasters.)

What is a volcano?
A volcano is a mountain that opens downward to a pool of molten rock below the surface of the earth. When pressure builds up, eruptions occur. Gases and rock shoot up through the opening and spill over or fill the air with lava fragments. Eruptions can cause lateral blasts, lava flows, hot ash flows, mudslides, avalanches, falling ash and floods. Volcano eruptions have been known to knock down entire forests. An erupting volcano can trigger tsunamis, flash floods, earthquakes, mudflows and rockfalls.

How are volcanoes formed?
Volcanoes are formed when magma from within the Earth's upper mantle works its way to the surface. At the surface, it erupts to form lava flows and ash deposits. Over time as the volcano continues to erupt, it will get bigger and bigger.

What are the different stages of volcanoes?
Scientists have categorized volcanoes into three main categories: active, dormant, and extinct. An active volcano is one which has recently erupted and there is a possibility that it may erupt soon. A dormant volcano is one which has not erupted in a long time but there is a possibility it can erupt in the future. An extinct volcano is one which has erupted thousands of years ago and there's no possibility of eruption.

Why do volcanoes erupt? The Earth's crust is made up of huge slabs called plates, which fit together like a jigsaw puzzle. These plates sometimes move. The friction causes earthquakes and volcanic eruptions near the edges of the plates. The theory that explains this process is called plate tectonics.

The theory of plate tectonics is a interesting story of continents drifting from place to place breaking apart, colliding, and grinding against each other. The plate tectonic theory is supported by a wide range of evidence that considers the earth's crust and upper mantle to be composed of several large, thin, relatively rigid plates that move relative to one another. The plates are all moving in different directions and at different speeds. Sometimes the plates crash together, pull apart or sideswipe each other. When this happens, it commonly results in earthquakes. What are plate tectonics?

Continental Drift: To see this animation again, just refresh this page! This animation shows you what our planet looked like millions of years ago and what it looks like now! (Graphic Credit: Geology Department at University of California, Berkeley)

There are more than 1500 active volcanoes on the Earth. We currently know of 80 or more which are under the oceans. Active volcanoes in the U.S. are found mainly in Hawaii, Alaska, California, Oregon and Washington.
How many volcanoes are there?

What are the different types of volcanoes?
Volcanoes are grouped into four types: cinder cones, composite volcanoes, shield volcanoes and lava volcanoes.

Cinder Cones

Cinder cones are circular or oval cones made up of small fragments of lava from a single vent that have been blown into the air, cooled and fallen around the vent.

Composite Volcanoes

Composite volcanoes are steep-sided volcanoes composed of many layers of volcanic rocks, usually made from high-viscosity lava, ash and rock debris. Mt. Rainier and Mount St. Helens are examples of this type of volcano.

Shield Volcanoes

Shield volcanoes are volcanoes shaped like a bowl or shield in the middle with long gentle slopes made by basaltic lava flows. Basalt lava flows from these volcanoes are called flood basalts. The volcanoes that formed the basalt of the Columbia Plateau were shield volcanoes.

Lava Volcanoes

Lava domes are formed when erupting lava is too thick to flow and makes a steep-sided mound as the lava piles up near the volcanic vent. The eruption of Mount St. Helens in 1980 was caused in part by a lava dome shifting to allow explosive gas and steam to escape from inside the mountain.

Magma is liquid rock inside a volcano. Lava is liquid rock (magma) that flows out of a volcano. Fresh lava glows red hot to white hot as it flows.

What is the difference between lava and magma?

Why does lava take a long time to cool down?
Lava cools slowly because lava is a poor conductor of heat. Lava flows slow down and thicken as they harden.
What is a pyroclastic flow?
A pyroclastic flow is a fluidized mixture of solid to semi-solid fragments and hot, expanding gases that flows down the sides of a volcano. These awesome features are heavier-than-air emulsions that move much like a snow avalanche, except that they are fiercely hot, contain toxic gases, and move at phenomenal, hurricane-force speeds. They are the most deadly of all volcanic phenomena.

What is lahar?
A lahar is a type of mudflow or debris flow composed of pyroclastic material, rocky debris, and water. The material flows down from a volcano, typically along a river valley. It is very dangerous because it's consistency and the way it acts is very much like cement. It is liquid when it's moving, but when it stops, it solidifies. This can cause just as much devastation as lava itself.
What is pumice?
Pumice is a light, porous volcanic rock that forms during explosive eruptions. It resembles a sponge because it consists of a network of gas bubbles frozen amidst fragile volcanic glass and minerals. All types of magma (basalt, andesite, dacite, and rhyolite) will form pumice.

What is the largest active volcano?
The world's largest, active volcano is Mauna Loa in Hawaii, where famous coffee is grown in the rich volcanic soils. Mauna Loa is 13,677 feet above sea level. From its base below sea level to its summit, Mauna Loa is taller than Mount Everest.

What is the Ring of Fire?

The Pacific Ring of Fire is an area of frequent earthquakes and volcanic eruptions encircling the basin of the Pacific Ocean. The Ring of Fire has 452 volcanoes and is home to over 50% of the world's active and dormant volcanoes. Ninety percent of the world's earthquakes and 81% of the world's largest earthquakes occur along the Ring of Fire.

When did Mount St. Helens erupt?
On May 18, 1980, Mount St. Helens erupted. It's located in southwestern Washington State in the Cascade Range. The blast was heard as far away as Montana, Idaho, Canada and California. Fifty-seven people died and the eruption caused $1.2 billion in damage.

What are some other notable volcano eruptions?
Krakatoa was a dormant volcano in Indonesia, which awakened and produced one of the biggest volcanic eruptions in 1883. So massive was the eruption that the sound of it was heard as far away as Australia. It's widely reported as the loudest sound heard in recorded history. The Krakatoa eruption created a huge amount of ash cloud which covered the Earth and reduced global temperatures for 5 years! A total of 40,000 people died in that explosion and an entire chain of the volcanic island was destroyed. For more info: Click Here!

Mount Pelee was a dormant volcano situated in the Caribbean island of Martinique. In 1902, it erupted in a massive horizontal explosion sending huge clouds of ash released towards the nearby town of Saint-Pierre. The side of the volcano exploded and lava flowed straight into the town, killing 30,000 people in a matter of minutes. It is regarded as one of the biggest and most devastating volcanic eruptions of the 20th century, a benchmark for future eruptions.

Mount Fujiyama, also popularly known as Mount Fuji, is an active volcano which last erupted in 1708. It is incidentally the tallest mountain in Japan. If you are visiting Tokyo, the capital of Japan, look in the west on a clear day and you will be able to see Mount Fuji. It is an iconic volcano. Mount Fuji is 3,776 meters high and it is snow clad throughout the year, with five lakes surrounding it. Currently in a state of dormancy, there has not been any eruption reported for more than 300 years. The last known eruption lasted for about 3 weeks during which it covered the surrounding villages with ash and cinders. Mount Fuji is now a popular tourist location with a large number of climbers actively scaling the mountain top.

What is a tsunami?
A tsunami is a large ocean wave usually caused by an underwater earthquake or a volcanic explosion. Tsunamis are NOT tidal waves. Tidal waves are caused by the forces of the moon, sun, and planets upon the tides, as well as the wind as it moves over the water. With typical waves, water flows in circles, but with a tsunami, water flows straight. This is why tsunamis cause so much damage!

Know the Lingo
MAGMA - Magma is the liquid rock inside a volcano.

LAVA - Lava is the liquid rock (magma) that flows out of a volcano. Lava glows red hot to white hot as it flows.

ACTIVE VOLCANO - An active volcano is one that erupts regularly.
Volcano Safety Tips
PLAN FOR A VOLCANO: First of all, have a disaster plan and know whether or not you are at risk for danger. Be prepared for mudslides, flash floods, earthquakes, ash falling, acid rain and tsunamis. Prepare a disaster supplies kit for your home and car. Include a first aid kit, canned food and a can opener, bottled water, battery-operated radio, flashlight, protective clothing, dust mask, goggles and sturdy shoes. Don't forget, know all of your evacuation routes. DURING A VOLCANO: Follow the evacuation order issued by authorities. Avoid areas downwind and river valleys downstream of the volcano. If your caught indoors, close all windows and doors, put machinery inside a barn, and bring animals inside. If you're trapped outdoors, seek shelter indoors. If you're caught in falling rocks, roll into a ball and protect your head. If you're caught near a stream, be aware of mudflows and move to higher ground. Protect yourself when ash falls by wearing long-sleeved shirts and long pants. Use goggles to protect your eyes. Wear a dust mask and keep car engines off.
DORMANT VOLCANO - A dormant volcano is one that has not erupted for many years, although there is still some activity deep inside. AFTER A VOLCANO: Cover you mouth and nose. Volcanic ash can irritate your respiratory system. Wear goggles and protect your eyes. Keep your skin covered. Clear roofs of ash, because the ash is very heavy and can cause the building to collapse.
Volcano Activities
Lesson Plan: Here are great lesson plans on learning more about volcanoes. These are great lesson plans for elementary school students.
EXTINCT VOLCANO - An extinct volcano is a volcano that is no longer active.Volcano Experiment: Here is an experiment on how to make a soda bottle volcano with Mentos.
Volcano Experiment: Here is another experiment on how to make a baking soda volcano.
GEYSERS - Geysers are springs that throw boiling water high in the air. They are caused by volcanic heat warming trapped ground water.Science Fair Project Ideas: Here is a complete list of science fair project ideas. Discover the science behind the weather that impacts us every day.

ASH - Ash are very small fragments of lava or rock blasted into the air by volcanic explosions.

PUMICE - It is a light-colored volcanic rock containing lots of bubbles from trapped gases.

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Weather Wiz Kids weather information for kids

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Weather Wiz Kids is a fun and safe website for kids about all the weather info they need to know. It contains tools for weather education, including weather games, activities, experiments, photos, a glossary and educational teaching materials for the classroom.

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Enjoy our awesome range of Earth facts for kids. Check out the cool trivia and have fun learning about some of our planet's most amazing features.

Tsunami Facts

Check out our tsunami facts for kids and learn some interesting information related to these great walls of water that can cause so much destruction. Find out what causes tsunamis and read about some notable recent examples of tsunamis that have occurred around the globe.

Tsunamis are huge waves of water that are usually caused by earthquakes or volcanic eruptions.

As a tsunami approaches the shore, water may recede from the coast, if it is shallow enough the water may be pulled back hundreds of metres. If you are in the area, observing this is a good indication that a tsunami is on the way.

Regions in tsunami danger zones often have warning systems in place to give people as much time to evacuate as possible.

When tsunamis hit shallow water (often near the coast) they slow down but increase in height.

An earthquake in the Indian Ocean off Indonesia in December 2004 caused a tsunami that killed over 200000 people in 14 countries. More earthquake facts.

In March 2011, the Tohoku earthquake off the eastern coast of Japan caused a tsunami that was a major factor in the death of over 15000 people.

The tsunami waves created by the Tohoku earthquake reached heights of over 40 metres (131 feet) in some areas, wiping out coastal towns and causing a number of nuclear accidents.

The Japanese word tsunami literally means 'harbor wave'.

Tsunamis are sometimes referred to as tidal waves but this term has fallen out of favour because tsunamis are not related to tides.

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Tsunami Facts for Kids - Interesting Information about Tsunamis

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Enjoy our awesome range of Earth facts for kids. Check out the cool trivia and have fun learning about some of our planet's most amazing features. Tsunami Facts Check out our tsunami facts for kids and learn some interesting information related to these great walls of water that can cause so much destruction.

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Kids learn about tsunamis including what causes them such as earthquakes, where they occur, why they are dangerous, and what happens during a tsunami event.

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Explore National Geographic. A world leader in geography, cartography and exploration.

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Scholastic Teaching Tools | Resources for Teachers

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Explore Scholastic Teaching Tools for teaching resources, printables, book lists, and more. Enhance your classroom experience with expert advice!

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Tornadoes are one of the most violent and powerful types of weather. They consist of a very fast rotating column of air that usually forms a funnel shape. They can be very dangerous as their high speed winds can break apart buildings, knock down trees, and even toss cars into the air.

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Kids learn about tornadoes including how they form, characteristics, types including supercell and waterspout, categories, and fun facts.

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The 10 deadliest US tornadoes on record | CNN

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Tornadoes are capable of tremendous destruction and can have devastating consequences. They are most common in the Central Plains and southeastern US, but they have been reported in all 50 states, according to the National Weather Service. Tornadoes kill an average of 60 people a year in the United States, according to the National Oceanic and Atmospheric Administration.

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The 10 deadliest US tornadoes on record | CNN

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Tornadoes are capable of tremendous destruction and can have devastating consequences. They are most common in the Central Plains and southeastern US, but they have been reported in all 50 states, according to the National Weather Service. Tornadoes kill an average of 60 people a year in the United States, according to the National Oceanic and Atmospheric Administration.

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Weather Wiz Kids weather information for kids

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Weather Wiz Kids is a fun and safe website for kids about all the weather info they need to know. It contains tools for weather education, including weather games, activities, experiments, photos, a glossary and educational teaching materials for the classroom.

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A shifting of tectonic plates, an underwater earthquake, a tidal surge and then--Tsunami! Learn about these forces of nature from Tim and Moby.

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Come out of your basement and click on this weather movie about twisters, the windy natural disasters caused by changes in air pressure and wind direction!

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Learn how local weather and climate conditions can lead to long-term water shortages.

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BrainPOP - Animated Educational Site for Kids - Science, Social Studies, English, Math, Arts & Music, Health, and Technology

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Scholastic Teaching Tools | Resources for Teachers

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Extreme Weather and Natural Disasters
http://www.weatherwizkids.com/

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What is a drought?
A drought is when there is a lack of precipitation over an extended period of time, usually a season or more, resulting in a water shortage for some activity, group, or environmental sector. Its impacts result from the interplay between the natural event (less precipitation than expected) and the demand people place on water supply, and human activities can exacerbate the impacts of drought.

What causes a drought?
Drought has many causes. It can be caused by not receiving rain or snow over a period of time. If you live in a place where most of the water you use comes from a river, a drought in your area can be caused by places upstream from you not receiving enough moisture. There would be less water in the river for you and other people who live along the river to use. People can also play a big role in drought. If we use too much water during times of normal rainfall, we might not have enough water when a drought happens.

Can scientists predict if a drought is going to happen?
No! Studies conducted over the past century have shown that meteorological drought is never the result of a single cause. It is the result of many causes including, global weather patterns, high pressure, the tropical outlook and other global-scale variables.

Are there places in the United States that experience drought?
Yes! The Western United States is experiencing an exceptional and extreme drought at this time. To see the map, Click Here to see the current U.S. Drought Monitor.

What was the Dust Bowl?
Of all the droughts that have occurred in the United States, the drought events of the 1930s are widely considered to be the "drought of record" for the nation. The 1930s drought is often referred to as if it were one episode, but it was actually several distinct events occurring in such rapid succession that affected regions were not able to recover adequately before another drought began. The term Dust Bowl was coined in 1935 to describe the drought-affected south central United States in the aftermath of horrific dust storms. Although it technically refers to the western third of Kansas, southeastern Colorado, the Oklahoma Panhandle, the northern two-thirds of the Texas Panhandle, and northeastern New Mexico, the Dust Bowl has come to symbolize the hardships of the entire nation during the 1930s.

How bad was the drought in the Dust Bowl years?
In the 1930s, drought covered virtually the entire Plains for almost a decade. The drought's direct effect is most often remembered as agricultural. Many crops were damaged by deficient rainfall, high temperatures, and high winds, as well as insect infestations and dust storms that accompanied these conditions. The resulting agricultural depression contributed to the Great Depression's bank closures, business losses, increased unemployment, and other physical and emotional hardships. Although records focus on other problems, the lack of precipitation would also have affected wildlife and plant life, and would have created water shortages for domestic needs.

What was the Black Sunday Dust Storm?
The 1930s were times of tremendous hardship on the Great Plains. Settlers dealt not only with the Great Depression, but also with years of drought that plunged an already-suffering society into an onslaught of relentless dust storms for days and months on end. They were known as dirt storms, sand storms, black blizzards, and "dusters." It seemed as if it could get no worse, but on Sunday, the 14th of April 1935, it got worse. The day is known in history as "Black Sunday," when a mountain of blackness swept across the High Plains and instantly turned a warm, sunny afternoon into a horrible blackness that was darker than the darkest night. Famous songs were written about it, and on the following day, the world would hear the region referred to for the first time as "The Dust Bowl."

How does a drought affect our lives?
Drought affects our lives in many different ways because water is such an important part of so many of our activities. We need water to live, and animals and plants do too. We need water to grow the food we eat. We also use water for many different things in our lives, like washing dishes, cooking, bathing, and swimming or river rafting. Water is also used to help make the electricity we use to run the lights in our houses and the video games you may like to play. When we don't have enough water for these activities because of a drought, many people and many different things will be affected in many different ways.

How can we help if we're in a drought?
One of the easiest steps we can take to help mitigate the impacts of drought is conserving water. If we use water wisely at all times, more water will be available to us and to plants and wildlife when a drought happens. We can lose a lot of water doing simple everyday tasks. Did you know that turning off the water while you brush your teeth can save more than 100 gallons of water a month? If you have a leaky faucet, the drips can add up to 300 gallons of wasted water a month.

What are the different types of drought?
There are four basic approaches to measuring drought: meteorological, hydrological, agricultural, and socioeconomic. The first three approaches deal with ways to measure drought as a physical phenomenon. The last deals with drought in terms of supply and demand, tracking the effects of water shortfall as it ripples through socioeconomic systems.

Meteorological drought is defined usually on the basis of the degree of dryness (in comparison to some "normal" or average amount) and the duration of the dry period. Definitions of meteorological drought must be considered as region specific since the atmospheric conditions that result in deficiencies of precipitation are highly variable from region to region. For example, some definitions of meteorological drought identify periods of drought on the basis of the number of days with precipitation less than some specified threshold. This measure is only appropriate for regions characterized by a year-round precipitation regime such as a tropical rainforest, humid subtropical climate, or humid mid-latitude climate.

Agricultural drought links various characteristics of meteorological (or hydrological) drought to agricultural impacts, focusing on precipitation shortages, differences between actual and potential evapotranspiration, soil water deficits, reduced groundwater or reservoir levels, and so forth. Plant water demand depends on prevailing weather conditions, biological characteristics of the specific plant, its stage of growth, and the physical and biological properties of the soil. A good definition of agricultural drought should be able to account for the variable susceptibility of crops during different stages of crop development, from emergence to maturity.

Hydrological drought is associated with the effects of periods of precipitation (including snowfall) shortfalls on surface or subsurface water supply (i.e., streamflow, reservoir and lake levels, groundwater). The frequency and severity of hydrological drought is often defined on a watershed or river basin scale. Although all droughts originate with a deficiency of precipitation, hydrologists are more concerned with how this deficiency plays out through the hydrologic system. Hydrological droughts are usually out of phase with or lag the occurrence of meteorological and agricultural droughts. It takes longer for precipitation deficiencies to show up in components of the hydrological system such as soil moisture, streamflow, and groundwater and reservoir levels. As a result, these impacts are out of phase with impacts in other economic sectors.

Socioeconomic definitions of drought associate the supply and demand of some economic good with elements of meteorological, hydrological, and agricultural drought. It differs from the aforementioned types of drought because its occurrence depends on the time and space processes of supply and demand to identify or classify droughts. The supply of many economic goods, such as water, forage, food grains, fish, and hydroelectric power, depends on weather. Because of the natural variability of climate, water supply is ample in some years but unable to meet human and environmental needs in other years. Socioeconomic drought occurs when the demand for an economic good exceeds supply as a result of a weather-related shortfall in water supply.

Aquifer - an area that contains large amounts of water under the surface of the earth.

Climate - day-to-day weather over a longer period of time. Climatology is the study of climate.

Climograph - a graph that shows monthly average temperature and precipitation for some location.

Dam - a structure built across a river to hold back water for a variety of reasons, including protecting areas from floods, storing water, and generating power.

Desalination - the process of removing salts and other minerals from seawater so that it can be used for drinking water.

Drought - less rainfall than is expected over an extended period of time, usually several months or longer. Or, more formally, it is a deficiency of rainfall over a period of time, resulting in a water shortage for some activity, group, or environmental sector.

Drought Index - a numerical scale that scientists use to describe the severity of a drought. Scientists take many kinds of data (like streamflow, rainfall, temperature, and snowpack) and "blend" it into a single number, called a drought index value, to make it easier to understand the drought conditions of a particular area. Drought indices are one type of drought indicator.

Drought I ndicator - a way to look at one or more variables, such as precipitation, to describe available water in soil or hydrologic systems. It may be a record of a single measurement, such as rainfall at a particular rain gauge. It may also be a complex index. Drought indices (indexes) are a subset of drought indicators.

Dust Bowl - an area of the U.S. Plains that included parts of Kansas, Colorado, Oklahoma, Texas, and New Mexico. The term was coined in the 1930s, when dry weather and high winds caused many dust storms throughout the United States, but particularly in this area.

Erosion - a process that wears the earth's surface away, causing soil to move from one place to another. It's a natural process, but human activities can make it worse.

Groundwater - water that is found underground in spaces in soil, sand, or rocks.

Hydroelectricity - electricity created by channeling water through turbines in power stations located below dams.

Irrigation - an agricultural practice that involves providing water to crops through pipes, ditches, or streams.

Mitigation - actions that we can take before, or at the beginning of, drought to help reduce the impacts of drought. Mitigation includes actions as diverse as drought planning, implementing land use practices that increase the organic content and water-holding capacity of soil, and designing agricultural policy that doesn't encourage short-term economic gains at the expense of long-term productive capacity. The Intergovernmental Panel on Climate Change uses mitigation to mean reducing emissions of greenhouse gasses.

Reservoirs - water that's collected and stored in natural or manmade lakes.

Submarginal Farmland - lands with nutrient-poor soils and/or soils that have been damaged by poor cultivation practices.

Water Banking - a water management strategy that temporarily transfers water from those who are willing to lease it to those who are willing to pay to use it.

Water Recycling - reusing treated wastewater for purposes like agricultural and landscape irrigation. It's also referred to as water reclamation or water reuse.

Xeriscaping - a type of landscaping around homes and businesses that uses a limited amount of water.

Click on the chart to make larger!

Click Here to see the current U.S. Drought Monitor!

Lesson Plan: Here is a lesson plan on water conservation.

Lesson Plan: Here is a lesson plan on how drought affect agriculture.

Science Fair Project Ideas: Here is a complete list of science fair project ideas. Discover the science behind the weather that impacts us every day.

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What is a drought? A drought is when there is a lack of precipitation over an extended period of time, usually a season or more, resulting in a water shortage for some activity, group, or environmental sector.

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Rain & Floods

How does rain form?
Water droplets form from warm air. As the warm air rises in the sky it cools. Water vapor (invisible water in the air) always exists in our air. Warm air holds quite a bit of water. For example, in the summer it is usually very humid. When enough of these droplets collect together, we see them as clouds. If the clouds are big enough and have enough water droplets, the droplets bang together and form even bigger drops. When the drops get heavy, they fall because of gravity, and you see and feel rain.

What causes rain?

When clouds develop or rain occurs, something is making the air rise. Several things can make this happen. Mountains, low-pressure areas, cold fronts, and even the jet stream.

How big are raindrops?
Raindrops are much smaller than we think! They are actually smaller than a centimeter. Raindrops range from 1/100 inch (.0254 centimeter) to 1/4 inch (.635 centimeter) in diameter.

How fast do raindrops fall?
Not including wind-driven rain, raindrops fall between 7 and 18 miles per hour (3 and 8 meters per second) in still air. The range in speed depends on the the size of the raindrop. Air friction breaks up raindrops when they exceed 18 miles per hour.

What is a flood?
A flood results from days of heavy rain and/or melting snows, when rivers rise and go over their banks.

What is a flash flood?
A flash flood is sudden flooding that occurs when floodwaters rise rapidly with no warning within several hours of an intense rain. They often occur after intense rainfall from slow moving thunderstorms. In narrow canyons and valleys, floodwaters flow faster than on flatter ground and can be quite destructive.

Do flash floods hurt people?
Flash floods are the #1 weather-related killer in the U.S. Nearly 80% of flash flood deaths are auto related. Know beforehand if your area is a flood risk.

How much water is needed for your car to float away?
A mere 2 feet of water can float a large vehicle or even a bus. This is why you should never drive through flooded roads. Just 6 inches of rapidly moving flood water can knock a person down.

What is a monsoon?
A monsoon is a seasonal wind, found especially in Asia that reverses direction between summer and winter and often brings heavy rains. In the summer, a high pressure area lies over the Indian Ocean while a low exists over the Asian continent. The air masses move from the high pressure over the ocean to the low over the continent, bringing moisture-laden air to south Asia. During winter, the process is reversed and a low sits over the Indian Ocean while a high lies over the Tibetan plateau so air flows down the Himalaya and south to the ocean. The migration of trade winds and westerlies also contributes to the monsoons. Smaller monsoons take place in equatorial Africa, northern Australia, and, to a lesser extent, in the southwestern United States.

What is radar?
Radar is an electronic instrument, which determines the direction and distance of objects that reflect radio energy back to the radar site. It stands for Radio Detection and Ranging. This is what meteorologists use to see rain or snow.

What is Doppler Radar? Doppler Radar detects precipitation intensity, wind direction and speed, and provides estimates of hail size and rainfall amounts. Doppler Radar gives forecasters the capability of providing early detection of severe thunderstorms that may bring strong damaging winds, large hail, heavy rain, and possibly tornadoes. Combined with satellites, radar gives forecasters the ultimate tools to provide accurate forecasts and advanced severe weather warnings.

Doppler Radar gets its name from the Doppler Effect. Have you ever listened to a train whistle as it was coming toward you? You probably noticed that the pitch of the whistle changed as the train passed you and moved away. This change in the frequency of sound is called the Doppler Effect. Doppler Radar measures the changes in the frequency of the signal it receives to determine the wind. How does Doppler Radar work?

The National Weather Service has installed a new type of Doppler Radar called NEXRAD Radar. NEXRAD stands for Next Generation Radar. This radar produces many different views of storms and rain that allows meteorologists to determine if a storm could be severe.
What is NEXRAD Radar?

Know the Lingo

FLOOD WATCH - means that an overflow of water from a river is possible for your area.

FLASH FLOOD WATCH - means that flash flooding is possible in or close to the watch area. Flash Flood Watches can be put into effect for as long as 12 hours, while heavy rains move into and across the area.

FLOOD WARNING - means flooding conditions are actually occurring in the warning area.

FLASH FLOOD WARNING - means that flash flooding is actually occurring in the warning area. A warning can also be issued as a result of torrential rains, a dam failure or snow thaw.
Click Here to see if there are any active warnings in your area.
Flood Safety Tips

BEFORE A FLOOD: Have a disaster plan and prepare a disaster supplies kit for your home and car. Include a first aid kit, canned food, can opener, bottled water, battery-operated radio, flashlight, protective clothing and written instructions on how to turn off electricity, gas, and water.
DURING A FLOOD: Move to a safe area quickly. Move to higher ground, like the highest floor of your home. Avoid areas subject to sudden flooding like low spots and canyons. Avoid already flooded areas. If a flowing stream of water is above your ankles stop, turn around and go the other way. Do not attempt to drive through a flooded road. The depth of the water is not obvious and the road may be washed away. If your car stalls, leave it and seek higher ground. Rapidly rising water may engulf the car, pick it up and sweep it away. Kids should never play around high water, storm drains or viaducts. Be cautious at night, because its harder to see flood dangers. If told to evacuate, do so immediately.
AFTER THE FLOOD: Always, boil drinking water. Electrical equipment should be checked and dried before used.
Rain Activities

Lesson Plan: Here is a great lesson plan on learning about precipitation. In this activity, kids will use a weather map to answer questions about precipitation falling across the country. Note: This is a PDF file, so you need to have Adobe Acrobat Reader.

Pressure Experiment: Here is an experiment that shows how pressure is created in our atmosphere by sucking an egg in a bottle. This is a very cool experiment!

Science Fair Project Ideas: Here is a complete list of science fair project ideas. Discover the science behind the weather that impacts us every day.Make A Barometer Experiment: Here is an experiment that allows the kids to make a barometer.

Evaporation Experiment: Here is an experiment that shows kids how evaporation takes place.

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Weather Wiz Kids weather information for kids

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Kids learn about tsunamis including what causes them such as earthquakes, where they occur, why they are dangerous, and what happens during a tsunami event.

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What is a tsunami?
A tsunami is a large ocean wave usually caused by an underwater earthquake or a volcanic explosion. Tsunamis are NOT tidal waves. Tidal waves are caused by the forces of the moon, sun, and planets upon the tides, as well as the wind as it moves over the water. With typical waves, water flows in circles, but with a tsunami, water flows straight. This is why tsunamis cause so much damage!

How are tsunamis generated?
Tsunamis are generated by any large, impulsive displacement of the sea level. The most common cause of a tsunami is sea floor uplift associated with an earthquake. Tsunamis are also triggered by landslides into or under the water surface, and can be generated by volcanic activity and meteorite impacts.

How often do tsunamis occur?
On the average, two tsunamis occur per year throughout the world which inflict damage near the source. Approximately every 15 years a destructive, ocean-wide tsunami occurs.

Can strike-slip (horizontal motion) earthquakes trigger tsunamis?
Yes, approximately 10-15% of damaging tsunamis are triggered by strike-slip earthquakes. This type of earthquake is less likely to trigger a tsunami than one with vertical motion. The waves are likely generated by associated landslides or motion of a sloping bathymetric feature. Tsunamis generated by strike-slip earthquakes normally affect regions near the source only.

What does the word "tsunami" mean?
Tsunami (soo-NAH-mee) is a Japanese word meaning harbor wave.

How fast do tsunamis travel?
Tsunami velocity depends on the depth of water through which it travels. Velocity equals the square root of the product of the water depth times the acceleration of gravity. Tsunamis travel approximately 475 mph in 15,000 feet of water. In 100 feet of water the velocity drops to about 40 mph.

Did you know...A tsunami travels from the central Aleutian Islands to Hawaii in about 5 hours and to California in about 6 hours, or from the Portugal coast to North Carolina in about 8.5 hours.

How big is a tsunami?
Tsunamis range in size from inches to over a hundred feet. In deep water (greater than 600 feet), tsunamis are rarely over 3 feet and are not normally noticed by ships due to their long period or time between crests. As tsunamis propagate into shallow water, the wave height can increase by over 10 times. Tsunami heights vary greatly along a coast. The waves can be amplified by shoreline and sea floor features. A large tsunami can flood low-lying coastal land over a mile from the coast.

What does a tsunami look like when it reaches shore?
Normally, a tsunami appears as a rapidly advancing or receding tide. In some cases, a wall of water or series of breaking waves may form.

How is a tsunami different from a wind-generated wave?
Wind-generated waves usually have periods or time between crests between 5 and 15 seconds. Tsunami periods normally range from 5 to 60 minutes. Also, wind-generated waves break as they shoal and lose energy offshore. Tsunamis act more like a flooding wave. A twenty foot tsunami is a twenty foot rise in sea level.

What are nature's signs that a tsunami may be imminent?
There are a few signs like hard ground shaking for 20+ seconds near the coast or a sudden sea level withdrawal. Tsunamis may be accompanied by loud, booming noises.

Can earthquakes and tsunamis be predicted?
No, earthquakes cannot be predicted. Once an earthquake has occurred, the arrival time of a tsunami, if generated, can be determined accurately. There is not normally enough time to accurately predict tsunami heights near the source. Away from the source, tsunami wave heights can be estimated based on mathematical tsunami models and observed wave heights.

Aerial video of the tsunami that devastated Japan on March 11, 2011.

Click Here to see an animation of an earthquake and the resulting tsunami. It's great for kids, because they get to see how it actually happens!
What are some of the most damaging tsunamis?

Japan: Major tsunami in 2011 generated in the Pacific Ocean.

Asia: Asian tsunami in 2004 generated in the Indian Ocean.

Alaska: Major tsunamis were generated along the Alaskan coast in 1946, 1957, 1958, 1964, and 1965. Many other locally generated tsunamis occurred prior to those dates.

US/Canada West Coast: Tsunamis were generated locally in 1812, 1873, 1878, 1927, 1930, 1946 and 1949. The west coast was also impacted by tsunamis generated in other regions in 1877, 1946, 1952, 1957, 1960, 1964, 1975, 2006, and 2010.

US/Canada Atlantic Coast: Tsunamis were recorded in 1755, 1884, 1886, and 1929.

Puerto Rico and the Virgin Islands experienced damaging tsunamis in 1867 and 1918.

Click Here for the NOAA/National Geophysical Data Center tsunami catalog.

TSUNAMI WARNING- A tsunami warning indicates that a tsunami may be imminent and that coastal locations in the warned area should prepare for flooding. The initial warning is typically based solely on seismic information. After the tsunami is recorded on sea level gages, the warning will be cancelled, restricted, expanded, or downgraded to an advisory. Warnings indicate that flooding up to the maximum expected limit is possible and residents should follow their local emergency management instructions. Warnings are issued when the earthquake information or tsunami forecasts indicate that a wave over 1 meter in amplitude is expected, possible, or ongoing.

TSUNAMI ADVISORY- A tsunami advisory indicates a tsunami which may produce strong currents and is dangerous to those in or very near the water is expected. Large inundations are not expected in areas under advisory status. Advisories will be cancelled, extended, or upgraded to a warning depending on the event severity. Advisories are issued when the tsunami forecast is in the range of 0.3 to 1 meter, or an observed tsunami is in the range of 0.5 to 1.0 meters.

TSUNAMI WATCH- A tsunami watch is an early alert issued to areas which may later be impacted by a tsunami. Tsunami impact is normally at least three hours away for regions within a tsunami watch. The watch will either be upgraded to a warning or advisory in subsequent messages or cancelled depending on the severity of the tsunami. People within a watch area should stay alert for further information regarding tsunami threat.

CREST - The top of a wave.

FJORD - A narrow sea inlet between cliffs or steep slopes.

SURGE - A large wave or billow.

TROUGH - The lowest point between waves.

Click Here to get the latest tsunami warning information from the NWS.

PLAN FOR A TSUNAMI: Have a disaster plan. Know whether you're at risk for danger. Plan an evacuation route. Prepare a disaster supplies kit for your home and car. Include a first aid kit, canned food and a can opener, bottled water, battery-operated radio, flashlight, protective clothing and written instructions on how to turn off electricity, gas, and water.

DURING A TSUNAMI: Follow the instructions issued by local authorities. You will probably want to evacuate immediately. Get to higher ground and as far inland as you can.

AFTER A TSUNAMI: Help injured or trapped people. Stay out of a building if water remains around it. Tsunami waters can cause buildings to sink, floors to crack, or walls to collapse. When re-entering homes, use extreme caution. Check for gas leaks. Open windows and doors to help dry things out. Look for fire hazards.

Lesson Plan: Here is a great lesson plan on learning about tsunamis. Note: This is a PDF file, so you need to have Adobe Acrobat Reader.

Lesson Plan: Here is a great lesson plan on tracking a tsunami.

Lesson Plan: Here is a great lesson plan on tsunamis and how they devastating effects they may cause in the world.

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What is a tsunami? A tsunami is a large ocean wave usually caused by an underwater earthquake or a volcanic explosion. Tsunamis are NOT tidal waves. Tidal waves are caused by the forces of the moon, sun, and planets upon the tides, as well as the wind as it moves over the water.

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They can speed across the ocean as fast as a jet plane, swallow up islands and wipe out villages.

But what causes tsuamis...? Join National Geographic Kids and dive into our tsunami facts to find out!

What causes a tsunami?

Meaning " great harbour wave" in Japanese, tsunamis are sometimes called "tidal waves" but their strength has nothing to do with the tides. About four out of five tsunamis happen within the Ring Of Fire, a zone in the Pacific Ocean where earthquakes and volcanic eruptions frequently take place.

Giant slabs of the Earth's crust, called tectonic plates, grind together. Sometimes, though, the plates get stuck, the pressure builds up and they suddenly slam into a new position. This causes an earthquake. If an earthquake lifts or drops part of the ocean floor, the water above rises and starts spreading across the ocean, causing a tsunami. Underwater landslides or volcanic eruptions can also displace water (cause water to spread across the ocean) and may lead to a tsunami.

How big is a tsunami?

Out in the open ocean, tsunami waves are only about one-metre high because the water is deep. However, as the water becomes shallow, the waves slow down and begin to grow. They can rise 35m or higher - that's the same as a 10-floor block of flats! However, the scariest thing about a tsunami is its wavelength, as this determines how far inland it can travel. Whereas a large wave caused by a storm might have a wavelength of up to 150m, a tsunami could reach up to a fearsome 1,000km!

How fast is a tsunami?

A normal wind wave travels at about 90kmh, but a tsunami can race across the ocean at an incredible 970kmh! Sometimes, before a tsunami hits, there is a huge vacuum effect, sucking water from harbours and beaches. People can see the ocean floor littered with flopping fish and other sea animals. Then a wave blasts onto the shore minutes later, then another and another for two hours or more. There may also be up to one hour between each wave.

Can you predict when a tsunami is coming?

To save lives, scientists established the Pacific Tsunami Warning System, based in Hawaii, in the USA. Its network of detectors can track quakes that may cause a tsunami. These waves can race from one side of the Pacific Ocean to the other in less than a day, so people need to be warned in time to head for higher ground!

What do you think of these tsunami facts? Let us know by leaving a comment, below!

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Tsunami facts: check out the mighty wave! - National Geographic Kids

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They can speed across the ocean as fast as a jet plane, swallow up islands and wipe out villages. But what causes tsuamis...? Join National Geographic Kids and dive into our tsunami facts to find out! Meaning " great harbour wave" in Japanese, tsunamis are sometimes called "tidal waves" but their strength has nothing to do with the tides.

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The wind at the beach is whipping at 95 miles an hour. Waves 16 feet tall are crashing down. Even sharks are heading out to calmer waters. A hurricane is on its way.

These powerful storms have different names depending on where in the world they form. They're called hurricanes if they occur in the Atlantic Ocean, Caribbean Sea, Gulf of Mexico, and eastern Pacific Ocean. In the western Pacific Ocean, they're known as typhoons; in the southern Pacific and Indian Oceans, they're called cyclones.

Scientists know them all as tropical cyclones. As many as 150 occur around the world each year.

How a hurricane forms

Hurricanes are strong storms that start in the ocean and have winds of at least 74 miles an hour. In the Northern Hemisphere (the part of Earth north of the equator), hurricanes generally occur between mid-August to late October. In the Southern Hemisphere (the area south of the equator), storm season is between April and December, with peak storm activity around May and November. During these times, oceans have warmer water, which is what a hurricane needs to form.

Hurricanes begin when a tropical depression forms in the ocean. A tropical depression is a line of rain showers and weak thunderstorms that circle around an area of low air pressure. If the water is at least 79°F, a hurricane might form.

The low air pressure causes the hot, humid air from the ocean to rise in a spiral shape. As that warm air rises, it releases heat, cools down, and condenses into gusty bands of clouds and storms. The low-pressure area continues to suck up hot, moist air, and the spiral gets stronger and faster.

When winds reach 39 miles an hour, the tropical depression becomes a tropical storm. When winds reach 74 miles an hour, it's officially a hurricane.

As a hurricane moves over cooler water or hits land, it loses the warm water that fuels it and begins to weaken. But dangerous winds can still cause damage, and storm surges-when a strong storm pushes ocean water ashore-can flood coastal areas with more than 20 feet of water. Heavy rains and floods can continue far inland.

Understanding a hurricane's strength

Hurricanes are classified by wind speed and the amount of damage that scientists predict the storm will cause when it reaches land. (In the United States, this is done by the National Hurricane Center, part of the National Oceanic and Atmospheric Administration.)

For example, a Category 1 storm has wind speeds of 74 to 95 miles an hour and will probably damage some homes and cause a few power outages. But a Category 5 hurricane is considered a powerful, destructive storm. These storms have winds of 156 miles an hour or more and will likely cause so much damage that people must abandon their communities, which will need months to clean up.

These rankings can help predict the severity of an approaching storm, but any hurricane can be devastating. For instance, Hurricane Katrina was only a Category 3 storm when it hit the U.S. Gulf Coast around Louisiana and Mississippi in 2005. The storm caused over $100 billion in damages, and nearly 2,000 people died.

Predicting the path

Meteorologists can predict the path that a hurricane will travel-and where it will make landfall-by analyzing changes in temperature, cloud formations, and air circulation patterns. That data is gathered by specialized aircraft, satellites, and weather surveillance radar from above the Earth. Other scientific devices that float in the ocean can measure winds, waves, and air and sea temperatures.

The information from these tools is used to create computer forecasting models used by scientists to learn when a storm is forming, where it might travel, and how severe it will be. That can help local officials release warnings or even evacuation orders in order to keep people safe from the coming hurricane.

Naming hurricanes

Once a storm's wind speed reachers 39 miles an hour, it becomes a tropical storm and is given a name. The name is chosen from a list of about 20 names issued by the World Meteorological Organization at the beginning of the hurricane season. They alternate between female and male names.

But you won't see David, Katrina, Andrew, or Laura on that list-those hurricanes were so destructive that the names have been removed. And you won't hear of any hurricanes starting with Q, U, X, Y, or Z, since few names begin with those letters.

More powerful storms in the future?

In the future, scientists don't expect to see more hurricanes, but they do expect more powerful ones. That's because hurricanes get bigger more quickly in warmer water. As climate change causes ocean temperatures to rise, scientists predict that future hurricanes will be rainier and longer lasting.

How to survive a hurricane

The safest thing to do is to follow local instructions and leave the area, or evacuate, if officials say you should. Here are other tips for staying safe if a hurricane is headed your way.

Before a hurricane
* Know the evacuation routes in your neighborhood, and make sure your parents have put gas in the car.
* Check your yard to see if any branches are broken on trees and alert an adult if they are. (Those branches could break off and soar through a window!)
* Bring in anything that could blow away, like garbage cans and outdoor furniture.
* Close all your windows, storm shutters, blinds, and curtains.

During a hurricane
* If you haven't evacuated, stay indoors where it's safe.
* Fill all bathtubs and sinks with clean, cold water in case water lines are damaged or the supply becomes contaminated.
* Ride out the storm in an interior room, such as a hallway or closet on the lowest level of your house.
* Never go near a window, even if it's boarded up.
* If it looks like the storm is going to hit your home, lie on the floor under a table or another sturdy object.
* Limit the use of cell phones to free up space for emergency calls.

After a hurricane
* Listen to weather reports to make sure the storm has passed. A calm sky might be just the hurricane's eye, or center, and more storm fun will be on the way.
* If you evacuated, return only when officials say it's safe.
* Check all food for spoilage. Remember: If in doubt, throw it out.

Adapted from the Nat Geo Kids book Extreme Weather by Thomas Kostigen, revised for digital by Laura Goertzel

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The wind at the beach is whipping at 95 miles an hour. Waves 16 feet tall are crashing down. Even sharks are heading out to calmer waters. A hurricane is on its way. These powerful storms have different names depending on where in the world they form.

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Tornadoes are one of the most violent and powerful types of weather. They consist of a very fast rotating column of air that usually forms a funnel shape. They can be very dangerous as their high speed winds can break apart buildings, knock down trees, and even toss cars into the air.

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Kids learn about tornadoes including how they form, characteristics, types including supercell and waterspout, categories, and fun facts.

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Weather Wiz Kids weather information for kids

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Weather Wiz Kids is a fun and safe website for kids about all the weather info they need to know. It contains tools for weather education, including weather games, activities, experiments, photos, a glossary and educational teaching materials for the classroom.

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Take shelter, gang - because here at National Geographic Kids, we're entering the eye of the storm with ten tornado facts!

Check out our ten top facts about tornadoes...

1) Tornadoes - also known as "twisters" - are violently rotating columns of air that reach from a storm cloud to the earth's surface.

2) The winds of a tornado can reach speeds of up to 480km per hour - that's strong enough to peel the roofs off houses, uproot trees and hurl heavy objects, such as cars, hundreds of metres!

3) Tornadoes come in different shapes and sizes. Some may appear as wide funnel-shaped clouds, others as thin rope-like swirls stretching from the ground to the sky.

4) The duration of tornadoes, and the distance they travel, varies. Most last less than ten minutes and travel five to ten kilometres before disappearing. In extreme cases, however, they can last several hours and cross distances over 150km!

5) Tornadoes are measured using the Fujita Scale (or F-scale), ranging from F0 to F5, with F5 being the strongest and most destructive.

6) The deadliest tornado ever recorded was in Bangladesh in 1989. As it travelled through the Dhaka region of the country, more than 20 villages were destroyed and around 1,300 people were killed.

7) Most of the world's tornadoes occur in the United States in what's known as Tornado Alley. Stretching from west Texas to North Dakota, this area can see more than 200 tornadoes each year!

8) If a tornado occurs over water, it's called a waterspout.

9) Not all tornadoes are easy to see. In fact, they can be invisible until they pick up dust and debris, or a cloud forms within the spinning funnel.

10) The formation of a tornado is so complex that scientists still don't completely understand it. And what's more, the unpredictability of tornadoes makes them difficult - and dangerous - to study. A tornado will demolish everything in its path, including measuring equipment. And so, the secrets behind this incredible force of nature are yet to be discovered...

Photos: Getty Images UK

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Tornado Facts! - National Geographic Kids

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Take shelter, gang - because here at National Geographic Kids, we're entering the eye of the storm with ten tornado facts! Check out our ten top facts about tornadoes... 1) Tornadoes - also known as "twisters" - are violently rotating columns of air that reach from a storm cloud to the earth's surface.

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Hold on tight, gang - and we mean super tight! - because we're about to check out ten facts on one of nature's most powerful forces - hurricanes!

1. Hurricanes are giant tropical storms that produce heavy rainfall and super-strong winds.

2. Hurricanes form over warm ocean waters near the equator. The warm, moist air above the ocean surface rises, causing air from surrounding areas to be "sucked" in. This "new" air then becomes warm and moist, and rises, too, beginning a continuous cycle that forms clouds. The clouds then rotate with the spin of the Earth. If there is enough warm water to feed the storm, a hurricane forms!

3. Hurricanes rotate around a circular centre called the " eye ", where it is generally calm with no clouds. Surrounding the eye is the eye wall - the most dangerous part of the hurricane with the strongest winds, thickest clouds and heaviest rain!

4. Most hurricanes occur harmlessly out at sea. However, when they move towards land they can be incredibly dangerous and cause serious damage.

5. The strong spiraling winds of a hurricane can reach speeds of up to 320kmph - strong enough to rip up entire trees and destroy buildings!

6. In the southern hemisphere, hurricanes rotate in a clockwise direction, and in the northern hemisphere they rotate in an anti-clockwise direction. This is due to what's called the Coriolis Force, produced by the Earth's rotation.

7. When a hurricane reaches land it often produces a " storm surge". This is when the high winds drive the sea toward the shore, causing water levels to rise and creating large crashing waves. Storm surges can reach 6m high and extend to over 150km!

8. Hurricanes are also called cyclones and typhoons, depending on where they occur. In the Atlantic Ocean and Northwest Pacific they are hurricanes, in the Northwest Pacific they are typhoons and in the South Pacific and Indian Ocean they are cyclones.

9. The largest hurricane on record is Typhoon Tip, which occurred in 1979 in the northwest Pacific. With a diameter of around 2,220km, it was nearly half the size of the United States!

10. Hurricanes are given names by the World Meteorological Organisation (WMO) so that they can be distinguished. Each year, tropical storms are named in alphabetical order according to a list produced by the WMO. That name stays with the storm if it develops into a hurricane. The names can only be repeated after six years.

Photos: Getty Images UK

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10 Facts about Hurricanes! - National Geographic Kids

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Check out ten top facts about hurricanes here at National Geographic Kids! Learn how hurricanes form, what the world's biggest hurricane is and more!

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Disasters don’t plan ahead. You can. Know what disasters and hazards could affect your area and learn what to do before, during, and after each type of emergency.

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Disaster planning, response and recovery efforts must consider the unique needs and abilities of children, who make up roughly a quarter of the U.S. population.

Youth preparedness and including youth in emergency management is an essential part of engaging the whole community. As you and your organization prepare for, respond to and recover from disasters, use our resources to explore how you can provide services that assist youth and families with children.

Learn More at Ready.gov/Kids

Start a Youth Preparedness Program

Anyone can start a youth preparedness program, or join an existing one. The Youth Preparedness Catalogue is a great place to start if you are looking to implement a youth preparedness program or activity.

Building a youth preparedness program takes a lot of work. However, many resources are available to help you with the process. We'll walk you through seven steps to implementing a youth preparedness program, and provide checklists and workbooks to help along the way. Many of these resources are available in both Spanish and English.

Why Youth Preparedness?

Children make up about 25 percent of the population of the United States and are the future of our communities. While they face unique vulnerabilities, they can also play an important role during emergencies. However, many programs do not consider children in their planning. It is important that children know what to do in an emergency and that all disaster planning, preparedness, response, and recovery efforts include children's unique needs and abilities.

Getting Started

Youth preparedness is important to the resilience of any community. As the leader of a youth preparedness program, you are supporting the preparedness effort within your community.

Funding

To create a successful program, you will need the proper resources. This funding guide outlines a four-step approach to securing funding, including identifying the resources you need, engaging potential funders and keeping records of donations.

Risk Management

There are risks and liabilities to consider when putting together a youth preparedness program-just as there would be with any other program or activity. These documents present an approach for developing a risk management plan.

Planning Materials

Browse emergency operations plans (EOPs), reunification guidance and tools, and other resources to support organizations responsible for the temporary care of children and youth. These organizations may include healthcare, childcare, educational and juvenile justice residential facilities.

Helping Children Cope

Disasters can sometimes leave children and teens feeling frightened, confused and insecure. Their responses can be quite varied. Learn about helping children cope with their emotions on Ready.gov.

Policy

There are national policies and policy guidance in place to support your organization's preparedness efforts and continued provision of services before, during, and after disasters. While building your youth preparedness program, you may reference:

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Disaster planning, response and recovery efforts must consider the unique needs and abilities of children, who make up roughly a quarter of the U.S. population. Youth preparedness and including youth in emergency management is an essential part of engaging the whole community.

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A drought is a period of time when an area or region experiences below-normal precipitation. The lack of adequate precipitation, either rain or snow, can cause reduced soil moisture or groundwater, diminished stream flow, crop damage, and a general water shortage. Droughts are the second-most costly weather events after hurricanes.

Unlike with sudden weather events such as hurricanes, tornadoes, and thunderstorms, it is often difficult to pinpoint when a drought has started or when it has ended. The initial effects of a drought may be difficult to identify right away, so it may take weeks or months to determine that a drought has started. The end of a drought is hard to identify for the same reason. A drought may last for weeks, months, or even years. Sometimes, drought conditions can exist for a decade or more in a region. The longer a drought lasts, the greater the harmful effects it has on people.

Droughts affect people in a several ways. Access to clean drinking water is essential for all life, and sources of water may dwindle during a drought. Without the presence of water, people must bring in enough water from elsewhere to survive. Water is also needed for crops to grow. When not enough precipitation falls to naturally water crops, they must be watered by irrigation. Irrigation is possible only when there is enough water in nearby rivers, lakes, or streams, or from groundwater. During a drought, these water sources are diminished and may even dry up, preventing crops from being irrigated and causing them to die off.

One person studying these problems is Alexandra Cousteau, a National Geographic Emerging Explorer whose latest initiative is Blue Legacy. She started Blue Legacy to raise awareness that we live on a water planet and must take care of it. Cousteau, the granddaughter of the famed ocean explorer Jacques Cousteau, believes that water will be a crucial issue in this century. She predicts that water problems such as drought, storms, floods, and degraded water quality will create "water refugees:" people migrating in search of water. Cousteau stresses that we must do all we can to protect Earth's valuable freshwater resources.

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Below-average precipitation affects the amount of moisture in soil as well as the amount of water in streams, rivers, lakes, and groundwater.

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The Dust Bowl was the name given to the drought-stricken southern plains region of the United States, which suffered severe dust storms during a drought in the 1930s. As high winds and choking dust swept the region from Texas to Nebraska, people and livestock were killed and crops failed across the entire region. The Dust Bowl intensified the crushing economic impacts of the Great Depression and drove many farming families on a desperate migration in search of work and better living conditions.
WATCH: America: The Story of Us on HISTORY Vault
What Caused the Dust Bowl?

The Dust Bowl was caused by several economic and agricultural factors, including federal land policies, changes in regional weather, farm economics and other cultural factors. After the Civil War, a series of federal land acts coaxed pioneers westward by incentivizing farming in the Great Plains.

The Homestead Act of 1862, which provided settlers with 160 acres of public land, was followed by the Kinkaid Act of 1904 and the Enlarged Homestead Act of 1909. These acts led to a massive influx of new and inexperienced farmers across the Great Plains.

Many of these late nineteenth and early twentieth century settlers lived by the superstition "rain follows the plow." Emigrants, land speculators, politicians and even some scientists believed that homesteading and agriculture would permanently affect the climate of the semi-arid Great Plains region, making it more conducive to farming.

Manifest Destiny

This false belief was linked to Manifest Destiny -an attitude that Americans had a sacred duty to expand west. A series of wet years during the period created further misunderstanding of the region's ecology and led to the intensive cultivation of increasingly marginal lands that couldn't be reached by irrigation.

Rising wheat prices in the 1910s and 1920s and increased demand for wheat from Europe during World War I encouraged farmers to plow up millions of acres of native grassland to plant wheat, corn and other row crops. But as the United States entered the Great Depression, wheat prices plummeted. In desperation, farmers tore up even more grassland in an attempt to harvest a bumper crop and break even.

Crops began to fail with the onset of drought in 1931, exposing the bare, over-plowed farmland. Without deep-rooted prairie grasses to hold the soil in place, it began to blow away. Eroding soil led to massive dust storms and economic devastation-especially in the Southern Plains.

When Was the Dust Bowl?

The Dust Bowl, also known as "the Dirty Thirties," started in 1930 and lasted for about a decade, but its long-term economic impacts on the region lingered much longer.

Severe drought hit the Midwest and southern Great Plains in 1930. Massive dust storms began in 1931. A series of drought years followed, further exacerbating the environmental disaster.

By 1934, an estimated 35 million acres of formerly cultivated land had been rendered useless for farming, while another 125 million acres-an area roughly three-quarters the size of Texas-was rapidly losing its topsoil.

Regular rainfall returned to the region by the end of 1939, bringing the Dust Bowl years to a close. The economic effects, however, persisted. Population declines in the worst-hit counties-where the agricultural value of the land failed to recover-continued well into the 1950s.

'Black Blizzards' Strike America

During the Dust Bowl period, severe dust storms, often called "black blizzards," swept the Great Plains. Some of these carried topsoil from Texas and Oklahoma as far east as Washington, D.C. and New York City, and coated ships in the Atlantic Ocean with dust.

Billowing clouds of dust would darken the sky, sometimes for days at a time. In many places, the dust drifted like snow and residents had to clear it with shovels. Dust worked its way through the cracks of even well-sealed homes, leaving a coating on food, skin and furniture.

Some people developed "dust pneumonia" and experienced chest pain and difficulty breathing. It's unclear exactly how many people may have died from the condition. Estimates range from hundreds to several thousand people.

On May 11, 1934, a massive dust storm two miles high traveled 2,000 miles to the East Coast, blotting out monuments such as the Statue of Liberty and the U.S. Capitol.

The worst dust storm occurred on April 14, 1935. News reports called the event Black Sunday. A wall of blowing sand and dust started in the Oklahoma Panhandle and spread east. As many as three million tons of topsoil are estimated to have blown off the Great Plains during Black Sunday.

An Associated Press news report coined the term "Dust Bowl" after the Black Sunday dust storm.

New Deal Programs

President Franklin D. Roosevelt established a number of measures to help alleviate the plight of poor and displaced farmers. He also addressed the environmental degradation that had led to the Dust Bowl in the first place.
WATCH: How Artists Helped End the Great Depression
As part of Roosevelt's New Deal, Congress established the Soil Erosion Service and the Prairie States Forestry Project in 1935. These programs put local farmers to work planting trees as windbreaks on farms across the Great Plains. The Soil Erosion Service, now called the Natural Resources Conservation Service (NRCS) developed and promoted new farming techniques to combat the problem of soil erosion.

Okie Migration

Roughly 2.5 million people left the Dust Bowl states- Texas, New Mexico, Colorado, Nebraska, Kansas and Oklahoma-during the 1930s. It was one of the largest migrations in American history.

Oklahoma alone lost 440,000 people to migration. Many of them, poverty-stricken, traveled west looking for work. From 1935 to 1940, roughly 250,000 Oklahoma migrants moved to California. A third settled in the state's agriculturally rich San Joaquin Valley.

These Dust Bowl refugees were called "Okies." Okies faced discrimination, menial labor and pitiable wages upon reaching California. Many of them lived in shantytowns and tents along irrigation ditches. "Okie" soon became a term of disdain used to refer to any poor Dust Bowl migrant, regardless of their state of origin.
READ MORE: How the Dust Bowl Made Americans Refugees in Their Own Country

Dust Bowl in Arts and Culture

The Dust Bowl, and the suffering endured by those who survived it, captured the hearts and imaginations of the nation's artists, musicians and writers.

John Steinbeck memorialized the plight of the Okies in his 1939 novel The Grapes of Wrath. Photographer Dorothea Lange documented rural poverty with a series of photographs for FDR's Farm Securities Administration, and artist Alexandre Hogue achieved renown with his Dust Bowl landscapes.

Folk musician Woody Guthrie, and his semi-autobiographical first album Dust Bowl Ballads of 1940, told stories of economic hardship faced by Okies in California. Guthrie, an Oklahoma native, left his home state with thousands of others looking for work during the Dust Bowl.

Sources

FDR and the New Deal Response to an Environmental Catastrophe. Roosevelt Institute.
About The Dust Bowl. English Department; University of Illinois.
Dust Bowl Migration. University of California at Davis.
The Great Okie Migration. Smithsonian American Art Museum.
Okie Migrations. Oklahoma Historical Society.
What we learned from the Dust Bowl: lessons in science, policy, and adaptation. Population and Environment.
The Dust Bowl. Library of Congress.
Dust Bowl Ballads: Woody Guthrie. Smithsonian Folkways Recordings.
The Dust Bowl. Ken Burns; PBS.

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The Dust Bowl was the name given to the drought-stricken southern plains region of the United States, which suffered severe dust storms during a drought in the 1930s. As high winds and choking dust swept the region from Texas to Nebraska, people and livestock were killed and crops failed across the entire region.

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Earthquake Facts for Kids - Interesting Information about Earthquakes

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Earthquakes involve the powerful movement of rocks in the Earth’s crust. The rapid release of energy creates seismic waves that travel through the earth.

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Learn the science behind how earthquakes happen—and how you can stay safe if one hits.

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Rumble rumble rumble! Have you ever been in an earthquake? Some people go through them all the time. In California there are dozens every day but they are usually very small. You tend to remember the big ones. Earthquakes are the breaking and cracking of the rocks inside the continental plates.

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Science >> Earth Science for Kids

Weather - Hurricanes (Tropical Cyclones)

What is a hurricane?

A hurricane is a large rotating storm with high speed winds that forms over warm waters in tropical areas. Hurricanes have sustained winds of at least 74 miles per hour and an area of low air pressure in the center called the eye.

Different Names for Hurricanes

The scientific name for a hurricane is a tropical cyclone. Tropical cyclones go by different names in different places. In North America and the Caribbean they are called "hurricanes", in the Indian Ocean they are called "cyclones", and in Southeast Asia they are called "typhoons."

How do hurricanes form?

Hurricanes form over the warm ocean water of the tropics. When warm moist air over the water rises, it is replaced by cooler air. The cooler air will then warm and start to rise. This cycle causes huge storm clouds to form. These storm clouds will begin to rotate with the spin of the Earth forming an organized system. If there is enough warm water, the cycle will continue and the storm clouds and wind speeds will grow causing a hurricane to form.

Parts of a Hurricane

Eye - At the center of the hurricane is the eye. The eye is an area of very low air pressure. There are generally no clouds in the eye and the wind is calm. Don't let this fool you, however, the most dangerous part of the storm is at the edge of the eye called the eye wall.

Eye wall - Around the outside of the eye is a wall made up of very heavy clouds. This is the most dangerous part of the hurricane and where the highest speed winds are. The winds at the eye wall can reach speeds of 155 miles per hour.

Rainbands - Hurricanes have large spirally bands of rain called rainbands. These bands can drop huge amounts of rainfall causing flooding when the hurricane hits land.

Diameter - Hurricanes can become huge storms. The diameter of the hurricane is measured from one side to the other. Hurricanes can span a diameter of over 600 miles.

Height - The storm clouds that power hurricanes can become very tall. A powerful hurricane can reach nine miles into the atmosphere.

The structure of a hurricane

Where do tropical cyclones occur?

Tropical cyclones occur over the ocean in areas near the equator. This is because there is plenty of warm water in these areas to allow the storms to form. There are seven major areas in the world that tend to produce tropical cyclones. See the map below.

Locations of tropical cyclones throughout the world

When do hurricanes occur?

Hurricanes that form in the Caribbean and the Atlantic Ocean occur between June 1st and November 30th each year. This is called hurricane season.

Why are hurricanes dangerous?

When hurricanes strike land they can cause huge amounts of damage. Most of the damage is caused by flooding and storm surge. Storm surge is when the ocean level rises at the coastline due to the power of the storm. Hurricanes also cause damage with high speed winds that can blow downtrees and damage homes. Many hurricanes can develop several small tornados as well.

How are they named?

Hurricanes in the Atlantic are named based on a list of names maintained by the World Meteorological Organization. The names go in alphabetical order and the storms are named as they appear. So the first storm of the year will always have a name that starts with the letter "A." There are six lists of names and each year a new list is used.

Categories

Tropical cyclones are categorized according to the speed of sustained winds.

Tropical Depression - 38 mph or less

Tropical Storm - 39 to 73 mph

Hurricane

Category 1 - 74 to 95 mph

Category 2 - 96 to 110 mph

Category 3 - 111 to 129 mph

Category 4 - 130 to 156 mph

Category 5 - 157 or higher mph

Interesting Facts about Hurricanes

Hurricanes rotate counterclockwise in the northern hemisphere and clockwise in the southern hemisphere. This is due to the rotation of the Earth called the Coriolis effect.

The letters Q, U, X, Y, and Z are not used for the first letter when naming hurricanes.

The names are alternated between boy and girl names.

Weather forecasters draw a cone showing where they think the hurricane is most likely to travel.

You can always find out the latest information on hurricanes at the website of the National Hurricane Center which tracks and forecasts hurricanes.

Activities

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Earth Science Subjects

Science >> Earth Science for Kids

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Kids learn about hurricanes (Tropical Cyclones) including how they form, names, eye, eye wall, rainbands, locations, seasons, facts, and categories.

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In the Grip of Epic Drought

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Almost every year, a large earthquake occurs somewhere in the world and captures the public's attention. Meanwhile, every day thousands of smaller tremors often go unnoticed by most people. Although we usually consider the ground to be solid and stable, the earth is, in fact, constantly shifting under our feet.

What causes earthquakes?

Earth's crust ranges from 3 to 45 miles deep (5 to 70 kilometers). The crust is a thin, hard shell that floats on the denser, hotter rock of the mantle. The crust is divided into several pieces known as tectonic plates that are constantly in motion, grinding past one another at boundaries known as faults.

As they slide past one another, the tectonic plates snag on rough patches of rock. They lock together like Velcro. However, even though the fault boundaries are locked together, the plates still move, pulling at the entangled sections. This pulling can further crack the Earth's crust, creating more faults near the plate boundaries.

An earthquake occurs when the pressure built up along a fault becomes stronger than the pressure holding the rocks together. Then the rocks on either side of the fault suddenly rip apart, sometimes at supersonic speeds. The two sides of the fault slide past one another, releasing the pent-up pressure. Energy from this separation radiates outward in all directions, including towards the surface, where it is felt as an earthquake. [ The 10 Biggest Earthquakes in History]

Even though the tectonic plates slide at a regular rate over time, the way that faults release stored energy is different with each earthquake, said Shimon Wdowinski, a geophysicist at the University of Miami's Rosentiel School of Marine & Atmospheric Sciences. "Every earthquake doesn't repeat exactly what happened before. Sometimes there is a big earthquakes, sometimes there are two or three together," he told Live Science. "There is no regularity."

A large earthquake is often followed by aftershocks, which are smaller quakes that result from the crust adjusting to the main shock. These aftershocks can help scientists target the origin of the main quake, but can create problems for those suffering its aftermath.

Tsunamis

If the earthquake occurs in the ocean, it can push up powerful waves, known as tsunamis. The sudden upward or downward movement of the seafloor during an earthquake creates large tsunami waves, similar to a child splashing in the bathtub. Earthquakes can also trigger tsunamis by unleashing underwater landslides, which also displace huge amounts of seawater.

(Image credit: AP Photo/Eric Skitzi)

Measuring earthquakes

An earthquake's size, or magnitude, depends on how large its parent fault is and how much it has slipped. Because these faults extend from the surface down to several miles deep, geologists can't simply visit the source to calculate these numbers. Instead, they rely on a tool known as a seismograph, which measures seismic waves, or vibrations, from an earthquake.

An earthquake's magnitude is ranked on the moment magnitude scale, not the Richter scale. The moment magnitude scale provides a better idea of the shaking and possible damage from earthquakes of all kinds around the world. [ Related: Whatever Happened to the Richter Scale?]

Earthquakes with magnitudes less than 3 occur every day, and are generally not felt by people. A magnitude of 3 to 5 is considered minor, while a quake with a magnitude of 5 to 7 is moderate to strong. At the higher end, these quakes can be destructive to cities. Earthquakes from 7 to 8 are major; about 15 of these occur annually. Every year, at least one earthquake with a magnitude over 8 - a "great" quake - wreaks havoc. An earthquake with a magnitude of 10 has never been measured, but it would create widespread devastation. [ Scary Scenario: Devastating Earthquake Visualized]

By using the readings from at least three seismographs, geologists can triangulate the origin of the earthquake. At the fault, that origin is called the hypocenter; on the surface, the epicenter.

Most of the major earthquakes strike on well-known fault lines. Californians, for instance, are unlikely to be shocked if they feel the ground shuddering beneath their feet. But a draft map released by the U.S. Geological Survey in 2014 reveals that 42 out of the 50 states have a moderate to high seismic hazard risk.

(Image credit: John Nelson, IDV Solutions. )

Preparing for disaster

Scientists have not yet come up with a way to forecast earthquakes. Although animals are reputed to have a sixth sense when it comes to these vibrations, no research has confirmed it, much less determined how such predictions might occur. In many cases, animals are simply sensing the arrival of earthquake waves that go unnoticed by people.

However, scientists can identify locations that are likely to experience earthquakes in the future. For instance, along the tectonic plate boundary off the western shore of South America, researchers have mapped the location of historical earthquakes and found " seismic gaps" - zones with no recent large earthquake quakes. And indeed, scientists had forecast a major earthquake in a seismic gap near Maule, Chile, which was hit by a magnitude-8.8 temblor in 2010. "There have been some very successful forecasts based on the seismic gap theory," Wdowinski said.

Even without such forecasts, there are some basic things that can be done to prepare for an earthquake. The Federal Emergency Management Agency recommends that all families everywhere should have an emergency kit in their home and car, and communicate with your loved ones a plan for any type of disaster (not just for earthquakes). Such preparation can make a difference not only physically, but also emotionally.

If you live in known earthquake territory, make sure your shelves are firmly attached to the walls, with heavy objects on lower shelves. Keep heavy objects away from beds and sitting areas, and fasten fixtures such as large televisions to the walls. Locate a safe place in each room, under a sturdy desk or table, where you can seek refuge from falling objects. Reinforced doorways can be a safe shelter, but most indoor doorways are not strong enough; a sturdy desk is likely to provide more protection, according to the U.S Geological Survey.

"Earthquakes don't kill, buildings kill," Wdowinski said.

If you are outside, get into an open area, away from structures or bridges. According to FEMA, many deaths in the 1933 Long Beach earthquake occurred when people ran outside, only to be crushed by falling debris from collapsing structures. Remember that the shaking ground rarely causes injury or death; instead, it is the falling objects that result from the quake. If you are in a car, stop as soon as you are able, but stay inside the car. If you are at or near the beach, move quickly inland to avoid potential waves from tsunamis.

After an earthquake, proceed with caution. Remember that most earthquakes are generally followed by aftershocks. Keep an eye (and a nose) out for gas leaks. If you were inside during the quake, move outside. Listen for public service announcements; a battery-powered radio is ideal for your emergency kit.

(Image credit: Records of the Office of the Chief Skinal Officer)

Famous quakes

1811-1812 - Missouri. In the early 19th century, the New Madrid series of earthquakes rattled the central United States. No seismographs existed at the time, so researchers used historical eyewitness accounts to determine that the magnitudes of the quakes ranged between 7 and 8. Huge waves formed on the Mississippi, causing some portions of the river to appear to flow backward.

1906 - San Francisco, California, Magnitude: 8. About 3,000 people died from the earthquake, on the San Andreas Fault, and resulting fire.

1923 - Tokyo, Japan, Magnitude: 7.9. One of the world's most destructive earthquakes, more than 142,000 people died from collapsing buildings and the resulting firestorm. The quake also resulted in enormous tsunami waves.

1960 - Chile, Magnitude: 9.5. The largest earthquake ever recorded, the 1960 quake in Chile killed more than 1,600 people, with many of the deaths resulting from tsunamis. Waves reached 38 feet (11.5 meters) and carried debris as far as 2 miles (3.2 kilometers) inland.

1970 - Peru, Magnitude: 7.9. Approximately 66,000 people died, many from collapsed buildings and a post-earthquake avalanche.

2004 - Indonesia, Magnitude: 9.1. The third largest earthquake in the world in this century, the quake killed more than 227,000 people. Powerful tsunami waves crisscrossed the Indian Ocean and ravaged 12 Asian countries.

2011 - Japan, Magnitude: 9.0. More than 15,000 people were killed when an earthquake in northern Japan triggered a giant tsunami. The tsunami also overwhelmed a nuclear reactor, creating new problems for people in the midst of destruction. [ Japan Earthquake & Tsunami]
Additional reporting by senior writer Becky Oskin Additional resources:

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Earthquakes & Tsunamis: Causes & Information

# data[].attributes.attachment_link.description
Almost every year, a large earthquake occurs somewhere in the world and captures the public's attention. Meanwhile, every day thousands of smaller tremors often go unnoticed by most people. Although we usually consider the ground to be solid and stable, the earth is, in fact, constantly shifting under our feet.

# data[].attributes.attachment_link.readable_text
Almost every year, a large earthquake occurs somewhere in the world and captures the public's attention. Meanwhile, every day thousands of smaller tremors often go unnoticed by most people. Although we usually consider the ground to be solid and stable, the earth is, in fact, constantly shifting under our feet.

What causes earthquakes?

Earth's crust ranges from 3 to 45 miles deep (5 to 70 kilometers). The crust is a thin, hard shell that floats on the denser, hotter rock of the mantle. The crust is divided into several pieces known as tectonic plates that are constantly in motion, grinding past one another at boundaries known as faults.

As they slide past one another, the tectonic plates snag on rough patches of rock. They lock together like Velcro. However, even though the fault boundaries are locked together, the plates still move, pulling at the entangled sections. This pulling can further crack the Earth's crust, creating more faults near the plate boundaries.

An earthquake occurs when the pressure built up along a fault becomes stronger than the pressure holding the rocks together. Then the rocks on either side of the fault suddenly rip apart, sometimes at supersonic speeds. The two sides of the fault slide past one another, releasing the pent-up pressure. Energy from this separation radiates outward in all directions, including towards the surface, where it is felt as an earthquake. [ The 10 Biggest Earthquakes in History]

Even though the tectonic plates slide at a regular rate over time, the way that faults release stored energy is different with each earthquake, said Shimon Wdowinski, a geophysicist at the University of Miami's Rosentiel School of Marine & Atmospheric Sciences. "Every earthquake doesn't repeat exactly what happened before. Sometimes there is a big earthquakes, sometimes there are two or three together," he told Live Science. "There is no regularity."

A large earthquake is often followed by aftershocks, which are smaller quakes that result from the crust adjusting to the main shock. These aftershocks can help scientists target the origin of the main quake, but can create problems for those suffering its aftermath.

Tsunamis

If the earthquake occurs in the ocean, it can push up powerful waves, known as tsunamis. The sudden upward or downward movement of the seafloor during an earthquake creates large tsunami waves, similar to a child splashing in the bathtub. Earthquakes can also trigger tsunamis by unleashing underwater landslides, which also displace huge amounts of seawater.

(Image credit: AP Photo/Eric Skitzi)

Measuring earthquakes

An earthquake's size, or magnitude, depends on how large its parent fault is and how much it has slipped. Because these faults extend from the surface down to several miles deep, geologists can't simply visit the source to calculate these numbers. Instead, they rely on a tool known as a seismograph, which measures seismic waves, or vibrations, from an earthquake.

An earthquake's magnitude is ranked on the moment magnitude scale, not the Richter scale. The moment magnitude scale provides a better idea of the shaking and possible damage from earthquakes of all kinds around the world. [ Related: Whatever Happened to the Richter Scale?]

Earthquakes with magnitudes less than 3 occur every day, and are generally not felt by people. A magnitude of 3 to 5 is considered minor, while a quake with a magnitude of 5 to 7 is moderate to strong. At the higher end, these quakes can be destructive to cities. Earthquakes from 7 to 8 are major; about 15 of these occur annually. Every year, at least one earthquake with a magnitude over 8 - a "great" quake - wreaks havoc. An earthquake with a magnitude of 10 has never been measured, but it would create widespread devastation. [ Scary Scenario: Devastating Earthquake Visualized]

By using the readings from at least three seismographs, geologists can triangulate the origin of the earthquake. At the fault, that origin is called the hypocenter; on the surface, the epicenter.

Most of the major earthquakes strike on well-known fault lines. Californians, for instance, are unlikely to be shocked if they feel the ground shuddering beneath their feet. But a draft map released by the U.S. Geological Survey in 2014 reveals that 42 out of the 50 states have a moderate to high seismic hazard risk.

(Image credit: John Nelson, IDV Solutions. )

Preparing for disaster

Scientists have not yet come up with a way to forecast earthquakes. Although animals are reputed to have a sixth sense when it comes to these vibrations, no research has confirmed it, much less determined how such predictions might occur. In many cases, animals are simply sensing the arrival of earthquake waves that go unnoticed by people.

However, scientists can identify locations that are likely to experience earthquakes in the future. For instance, along the tectonic plate boundary off the western shore of South America, researchers have mapped the location of historical earthquakes and found " seismic gaps" - zones with no recent large earthquake quakes. And indeed, scientists had forecast a major earthquake in a seismic gap near Maule, Chile, which was hit by a magnitude-8.8 temblor in 2010. "There have been some very successful forecasts based on the seismic gap theory," Wdowinski said.

Even without such forecasts, there are some basic things that can be done to prepare for an earthquake. The Federal Emergency Management Agency recommends that all families everywhere should have an emergency kit in their home and car, and communicate with your loved ones a plan for any type of disaster (not just for earthquakes). Such preparation can make a difference not only physically, but also emotionally.

If you live in known earthquake territory, make sure your shelves are firmly attached to the walls, with heavy objects on lower shelves. Keep heavy objects away from beds and sitting areas, and fasten fixtures such as large televisions to the walls. Locate a safe place in each room, under a sturdy desk or table, where you can seek refuge from falling objects. Reinforced doorways can be a safe shelter, but most indoor doorways are not strong enough; a sturdy desk is likely to provide more protection, according to the U.S Geological Survey.

"Earthquakes don't kill, buildings kill," Wdowinski said.

If you are outside, get into an open area, away from structures or bridges. According to FEMA, many deaths in the 1933 Long Beach earthquake occurred when people ran outside, only to be crushed by falling debris from collapsing structures. Remember that the shaking ground rarely causes injury or death; instead, it is the falling objects that result from the quake. If you are in a car, stop as soon as you are able, but stay inside the car. If you are at or near the beach, move quickly inland to avoid potential waves from tsunamis.

After an earthquake, proceed with caution. Remember that most earthquakes are generally followed by aftershocks. Keep an eye (and a nose) out for gas leaks. If you were inside during the quake, move outside. Listen for public service announcements; a battery-powered radio is ideal for your emergency kit.

(Image credit: Records of the Office of the Chief Skinal Officer)

Famous quakes

1811-1812 - Missouri. In the early 19th century, the New Madrid series of earthquakes rattled the central United States. No seismographs existed at the time, so researchers used historical eyewitness accounts to determine that the magnitudes of the quakes ranged between 7 and 8. Huge waves formed on the Mississippi, causing some portions of the river to appear to flow backward.

1906 - San Francisco, California, Magnitude: 8. About 3,000 people died from the earthquake, on the San Andreas Fault, and resulting fire.

1923 - Tokyo, Japan, Magnitude: 7.9. One of the world's most destructive earthquakes, more than 142,000 people died from collapsing buildings and the resulting firestorm. The quake also resulted in enormous tsunami waves.

1960 - Chile, Magnitude: 9.5. The largest earthquake ever recorded, the 1960 quake in Chile killed more than 1,600 people, with many of the deaths resulting from tsunamis. Waves reached 38 feet (11.5 meters) and carried debris as far as 2 miles (3.2 kilometers) inland.

1970 - Peru, Magnitude: 7.9. Approximately 66,000 people died, many from collapsed buildings and a post-earthquake avalanche.

2004 - Indonesia, Magnitude: 9.1. The third largest earthquake in the world in this century, the quake killed more than 227,000 people. Powerful tsunami waves crisscrossed the Indian Ocean and ravaged 12 Asian countries.

2011 - Japan, Magnitude: 9.0. More than 15,000 people were killed when an earthquake in northern Japan triggered a giant tsunami. The tsunami also overwhelmed a nuclear reactor, creating new problems for people in the midst of destruction. [ Japan Earthquake & Tsunami]
Additional reporting by senior writer Becky Oskin Additional resources:

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Earthquakes & Tsunamis: Causes & Information

# data[].attributes.attachment_link.description
Almost every year, a large earthquake occurs somewhere in the world and captures the public's attention. Meanwhile, every day thousands of smaller tremors often go unnoticed by most people. Although we usually consider the ground to be solid and stable, the earth is, in fact, constantly shifting under our feet.

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How does rain form?
Water droplets form from warm air. As the warm air rises in the sky it cools. Water vapor (invisible water in the air) always exists in our air. Warm air holds quite a bit of water. For example, in the summer it is usually very humid. When enough of these droplets collect together, we see them as clouds. If the clouds are big enough and have enough water droplets, the droplets bang together and form even bigger drops. When the drops get heavy, they fall because of gravity, and you see and feel rain.

What causes rain?
When clouds develop or rain occurs, something is making the air rise. Several things can make this happen. Mountains, low-pressure areas, cold fronts, and even the jet stream.

How big are raindrops?
Raindrops are much smaller than we think! They are actually smaller than a centimeter. Raindrops range from 1/100 inch (.0254 centimeter) to 1/4 inch (.635 centimeter) in diameter.

How fast do raindrops fall?
Not including wind-driven rain, raindrops fall between 7 and 18 miles per hour (3 and 8 meters per second) in still air. The range in speed depends on the the size of the raindrop. Air friction breaks up raindrops when they exceed 18 miles per hour.

What is virga?
Virga is an observable streak of water drops or ice particles falling out of a cloud and evaporating before reaching the ground.

What is a monsoon?
A monsoon is a seasonal wind, found especially in Asia that reverses direction between summer and winter and often brings heavy rains. In the summer, a high pressure area lies over the Indian Ocean while a low exists over the Asian continent. The air masses move from the high pressure over the ocean to the low over the continent, bringing moisture-laden air to south Asia. During winter, the process is reversed and a low sits over the Indian Ocean while a high lies over the Tibetan plateau so air flows down the Himalaya and south to the ocean. The migration of trade winds and westerlies also contributes to the monsoons. Smaller monsoons take place in equatorial Africa, northern Australia, and, to a lesser extent, in the southwestern United States.

What are sinkholes?
Sinkholes are pits in the ground that form in areas where water gathers without external drainage. As water drains below ground, it can dissolve subterranean caverns, particularly in areas where the bedrock is made of water-soluble evaporate rocks such as salt or gypsum or of carbonate rocks such as limestone or dolomite. Most of the time, sinkholes form gradually. Occasionally, though, the collapse is sudden. Those sudden sinkholes are often the ones that open up and swallow cars, homes and streets.

What are the different types of sinkholes?
Geologists divide sinkholes into three types. The first is a dissolution or solution sinkhole. In this type of sinkhole, there is little soil or vegetation over the limestone or other bedrock. Water from rain and runoff slowly trickles through crevices in the bedrock, dissolving it. As a result, a depression gradually forms. Dissolution sinkholes sometimes become ponds if the depression gets lined with debris, trapping water inside. Dissolution sinkholes happen slowly and are generally not dangerous, but one that becomes a pond can drain suddenly if water makes it through the protective bottom layer.

The second type of sinkhole is a cover-subsidence sinkhole. These sinkholes happen in areas where sand covers the bedrock. The sand filters down into openings in the rock, gradually causing the land surface to sink. Continued erosion increases the size of the depression. Like dissolution sinkholes, cover-subsidence sinkholes happen slowly.

The most dangerous type of sinkhole is a cover-collapse sinkhole. In these cases, the bedrock is covered by a layer of clay. Beneath this ground cover, however, water dissolves an underground cavern. Gradually, ground sediments begin to erode, or spall, into the cavern from the bottom. The ground continues to crumble from beneath until only a thin layer remains between the surface and the underground opening. When that layer collapses, the sinkhole opens up suddenly, swallowing any structures on top.

How do you measure rain?
Rain gauges provide the most accurate method of measuring rainfall at a single geographic point. To have operational value, the rain gauge report must be available in real time, and automated reporting networks are increasing. Real-time rain gauge networks are most useful for flash flood detection when WSR-88D rainfall estimates can be compared with the actual rain gauge values to determine the accuracy of the radar estimate.

What is a flood?
Flooding is an overflowing of water onto land that is normally dry. Floods can happen during heavy rains, when ocean waves come on shore, when snow melts too fast, or when dams or levees break. Flooding may happen with only a few inches of water, or it may cover a house to the rooftop. They can occur quickly or over a long period and may last days, weeks, or longer. Floods are the most common and widespread of all weather-related natural disasters.

What is a flash flood?
Flash floods are the most dangerous kind of floods, because they combine the destructive power of a flood with incredible speed and unpredictability. Flash floods occur when excessive water fills normally dry creeks or river beds along with currently flowing creeks and rivers, causing rapid rises of water in a short amount of time. They can happen with little or no warning.

Where and when do floods occur?
Flooding occurs in every U.S. state and territory, and is a threat experienced anywhere in the world that receives rain. In the U.S. floods kill more people each year than tornadoes, hurricanes or lightning.

How much water is needed for your car to float away?
A mere 2 feet of water can float a large vehicle or even a bus. This is why you should never drive through flooded roads. Just 6 inches of rapidly moving flood water can knock a person down.

What areas are at risk from flash floods?

Densely populated areas are at a high risk for flash floods. The construction of buildings, highways, driveways, and parking lots increases runoff by reducing the amount of rain absorbed by the ground. This runoff increases the flash flood potential. Sometimes, streams through cities and towns are routed underground into storm drains. During heavy rain, the storm drains can become overwhelmed and flood roads and buildings. Low spots, such as underpasses, underground parking garages, and basements can become death traps.

Areas near rivers are at risk from flash floods. Embankments, known as levees, are often built along rivers and are used to prevent high water from flooding bordering land. In 1993, many levees failed along the Mississippi River, resulting in devastating flash floods. The city of New Orleans experienced massive devastating flooding days after Hurricane Katrina came onshore in 2005 due to the failure of levees designed to protect the city.

Dam failures can send a sudden destructive wall of water downstream. In 1889 a dam break upstream from Johnstown, Pennsylvania, released a 30-40 foot wall of water that killed 2200 people within minutes.

Mountains and steep hills produce rapid runoff, which causes streams to rise quickly. Rocks and clay soils do not allow much water to infiltrate the ground. Saturated soil also can lead rapidly to flash flooding. Vacationing or recreating along streams or rivers can be a risk if there are thunderstorms in the area. A creek only 6 inches deep in mountainous areas can swell to a 10-foot deep raging river in less than an hour if a thunderstorm lingers over an area for an extended period of time.

Dry soil can produce flooding when very intense rainfall occurs. In the West, most canyons, small streams and dry arroyos are not easily recognizable as a source of danger. A wall of water 10-15 feet high can scour a canyon suddenly.

Ice jams and snowmelt can help cause flash floods. A deep snowpack increases runoff produced by melting snow. Heavy spring rains falling on melting snowpack can produce disastrous flash flooding. Melting snowpack may also contribute to flash floods produced by ice jams on creeks and rivers. Thick layers of ice often form on streams and rivers during the winter. Melting snow and/or warm rain running into the streams may lift and break this ice, allowing large chunks of ice to jam against bridges or other structures. This causes the water to rapidly rise behind the ice jam. If the water is suddenly released, serious flash flooding could occur downstream. Huge chunks of ice can be pushed onto the shore and through houses and buildings.

How do I know how severe a flood will be?
Once a river reaches flood stage, the flood severity categories used by the National Weather Service include minor flooding, moderate flooding, and major flooding. Each category has a definition based on property damage and public threat.

Minor Flooding-minimal or no property damage, but possibly some public threat or inconvenience

Moderate Flooding-some inundation of structures and roads near streams. Some evacuations of people and/or transfer of property to higher elevations are necessary.

Major Flooding-extensive inundation of structures and roads. Significant evacuations of people and/or transfer of property to higher elevations.

What were some of the worst floods in U.S. history?
The worst flood in U.S. history resulted from a dam break upstream from Johnstown, Pennsylvania, on May 31, 1889. Although ample warnings were given, they were disregarded by many townspeople, and 2,200 residents died.

Hurricane Katrina, a Category 4 hurricane along the eastern LA-western MS coastlines in August 2005, resulted in severe storm surge damage (maximum surge probably exceeded 25 feet) along the LA-MS-AL coasts, wind damage, and the failure of parts of the levee system in New Orleans. Inland effects included high winds and some flooding in the states of AL, MS, FL, TN, KY, IN, OH, and GA. Preliminary estimate of well over $100 billion in damage/costs and more than 1200 fatalities.

On February 26, 1972, the Buffalo Creek Dam located in southern West Virginia collapsed sending a black wave of water through one coal mining town after another, and killing more than 100 people. 4,000 people were left homeless.

On July 31, 1976, a storm in northern Colorado dumped a foot of rain into the Big Thompson Canyon producing a raging torrent of water 19 feet high and resulting in 145 deaths.

What is radar?
Radar is an electronic instrument, which determines the direction and distance of objects that reflect radio energy back to the radar site. It stands for Radio Detection and Ranging. This is what meteorologists use to see rain or snow.

What is Doppler Radar?
Doppler Radar detects precipitation intensity, wind direction and speed, and provides estimates of hail size and rainfall amounts. Doppler Radar gives forecasters the capability of providing early detection of severe thunderstorms that may bring strong damaging winds, large hail, heavy rain, and possibly tornadoes. Combined with satellites, radar gives forecasters the ultimate tools to provide accurate forecasts and advanced severe weather warnings.

How does Doppler Radar work?
Doppler Radar gets its name from the Doppler Effect. Have you ever listened to a train whistle as it was coming toward you? You probably noticed that the pitch of the whistle changed as the train passed you and moved away. This change in the frequency of sound is called the Doppler Effect. Doppler Radar measures the changes in the frequency of the signal it receives to determine the wind.

What is NEXRAD Radar?
The National Weather Service has installed a new type of Doppler Radar called NEXRAD Radar. NEXRAD stands for Next Generation Radar. This radar produces many different views of storms and rain that allows meteorologists to determine if a storm could be severe.

What are WSR-88D radars?
They graphically display detected precipitation on a map. Radar can show the location of the intense rainfall cores, and estimate the duration of rainfall. Radar can also track the evolution of storm systems over time. Forecasters are able to watch existing storm cells intensify, and see when new cells begin to develop. Animation of radar provides specific information on the movement of storm systems and helps in the assessment of the flash flood threat.

Currently, the NWS uses products developed for WSR-88D radars to aid in issuing flash flood statements, watches, or warnings. One product estimates one-hour precipitation accumulation to assess rainfall intensities for flash flood warnings, urban flood statements and special weather statements. Another product estimates accumulated rainfall, continuously updated, since the last one-hour break in precipitation. This product is used to locate flood potential over urban or rural areas, estimate total basin runoff and provide rainfall accumulations for the duration of the event.

FLOOD WATCH - means that an overflow of water from a river is possible for your area.

FLASH FLOOD WATCH - means that flash flooding is possible in or close to the watch area. Flash Flood Watches can be put into effect for as long as 12 hours, while heavy rains move into and across the area.

FLOOD WARNING - means flooding conditions are actually occurring in the warning area.

FLASH FLOOD WARNING - means that flash flooding is actually occurring in the warning area. A warning can also be issued as a result of torrential rains, a dam failure or snow thaw.

URBAN and SMALL STREAM ADVISORY - means flooding of small streams, streets and low-lying areas, such as railroad underpasses and urban storm drains is occurring.

Click Here to see if there are any active warnings in your area.

BEFORE A FLOOD: Have a disaster plan and prepare a disaster supplies kit for your home and car. Include a first aid kit, canned food, can opener, bottled water, battery-operated radio, flashlight, protective clothing and written instructions on how to turn off electricity, gas, and water.

DURING A FLOOD: Move to a safe area quickly. Move to higher ground, like the highest floor of your home. Avoid areas subject to sudden flooding like low spots and canyons. Avoid already flooded areas. If a flowing stream of water is above your ankles stop, turn around and go the other way. Do not attempt to drive through a flooded road. The depth of the water is not obvious and the road may be washed away. If your car stalls, leave it and seek higher ground. Rapidly rising water may engulf the car, pick it up and sweep it away. Kids should never play around high water, storm drains or viaducts. Be cautious at night, because its harder to see flood dangers. If told to evacuate, do so immediately.

AFTER THE FLOOD: Always, boil drinking water. Electrical equipment should be checked and dried before used.

Mudslides occur during periods of intense rainfall or rapid snowmelt. They usually start on steep hillsides, liquefy and accelerate down the hill. The debris flow ranges from watery mud to thick, rocky mud that can carry large items such as boulders, trees and cars. On average, mudslides cause 25 to 50 deaths each year. Always listen to the radio and television for the latest information and instructions for your area.

BEFORE INTENSE STORMS: Have a disaster plan. Become familiar with the land around you. Find out if you're in a mudslide prone area.

DURING INTENSE STORMS: Stay awake and alert. If you live in mudslide prone areas, consider leaving if it safe to do so. If you can't, go to the highest level of your home. Listen for unusual sounds that might indicate moving debris, such as trees cracking or boulders knocking each other. Be alert especially when driving. Watch the road for collapsed pavement, mud, fallen rocks and other indications of a possible debris flow.

DURING A MUDSLIDE: Quickly move out of the path of the mudslide. If you can't escape, curl into a tight ball and protect your head.

AFTER A MUDSLIDE: Stay away from mudslide areas. Check for injured or trapped people near the mudslide, without directly entering the area. Watch out for flooding which can happen after a mudslide. Check the foundation of your home, chimney and surrounding land for damage.

Lesson Plan: Here is a great lesson plan on learning about precipitation. In this activity, kids will use a weather map to answer questions about precipitation falling across the country. Note: This is a PDF file, so you need to have Adobe Acrobat Reader.

Make It Rain Experiment: Here is a great experiment on making rain. In this experiment, kids learn about condensation.

What's In The Rain Experiment: Here is an experiment that lets kids see what's in the rain. It shows kids that there are particles in the air and when it rains they get to see them up close.

Make A Rain Gauge Experiment: Here is an experiment that allows a kids to make their very own rain gauge.

See A Raindrop Experiment: Here is an experiment that allows you to see a raindrop. In this experiment, kids will preserve raindrops, so they can measure to see how big they really are.

Water Cycle Experiment: Here is an experiment that teaches kids about our water cycle. This experiment shows what happens to the water in our creeks, streams, rivers, lakes and oceans.

The Doppler Effect Experiment: Here is an experiment that teaches kids what the Doppler Effect is. They can learn how the Doppler Effect works and why Doppler Radar is such as important tool in weather forecasting.

Suck An Egg Into A Bottle Experiment: Here is an experiment that shows how pressure is created in our atmosphere by sucking an egg in a bottle. This is a very cool experiment!

Make Your Own Barometer I Experiment: Here is an experiment that allows the kids to make a barometer.

Make Your Own Barometer II Experiment: Here is an experiment that allows the kids to make a barometer.

Create Evaporation Experiment: Here is an experiment that shows kids how evaporation takes place.

Science Fair Project Ideas: Here is a complete list of science fair project ideas. Discover the science behind the weather that impacts us every day.

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How does rain form? Water droplets form from warm air. As the warm air rises in the sky it cools. Water vapor (invisible water in the air) always exists in our air. Warm air holds quite a bit of water. For example, in the summer it is usually very humid.

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What is a hurricane?
A hurricane is a huge storm! It can be up to 600 miles across and have strong winds spiraling inward and upward at speeds of 75 to 200 mph. Each hurricane usually lasts for over a week, moving 10-20 miles per hour over the open ocean. Hurricanes gather heat and energy through contact with warm ocean waters. Evaporation from the seawater increases their power. Hurricanes rotate in a counter-clockwise direction around an "eye" in the Northern Hemisphere and clockwise direction in the Southern Hemisphere. The center of the storm or "eye" is the calmest part. It has only light winds and fair weather. When they come onto land, the heavy rain, strong winds and large waves can damage buildings, trees and cars.

How do hurricanes form?
Hurricanes only form over really warm ocean water of 80°F or warmer. The atmosphere (the air) must cool off very quickly the higher you go. Also, the wind must be blowing in the same direction and at the same speed to force air upward from the ocean surface. Winds flow outward above the storm allowing the air below to rise. Hurricanes typically form between 5 to 15 degrees latitude north and south of the equator. The Coriolis Force is needed to create the spin in the hurricane and it becomes too weak near the equator, so hurricanes can never form there.
Hurricane Tracking Charts
Atlantic Ocean
Eastern Pacific

What is storm surge?
Storm surges are frequently the most devastating element of a hurricane. As a hurricane's winds spiral around and around the storm, they push water into a mound at the storm's center. This mound of water becomes dangerous when the storm reaches land because it causes flooding along the coast. The water piles up, unable to escape anywhere but on land as the storm carries it landward. A hurricane will cause more storm surge in areas where the ocean floor slopes gradually. This causes major flooding.
As you watch the storm-surge animations, notice the effect that the physical geography of each coastline has on storm surge. Also, note the waves on top of the ocean's surface. Wind, waves, and sea-level rise all contribute to storm-surge damage.

Shallow-Water Coastline

Deep-Water Coastline

With technology the way it is, there are computer models that allow forecasters to predict the amount of storm surge that will affect a coastal area. These are called Slosh Models and take into account a storm's strength, its path, how the ocean shallows, and the shape of the land. Then it calculates how much storm surge a hurricane will probably cause.

When does hurricane season start?
The Atlantic hurricane season is from June 1 to November 30, but most hurricanes occur during the fall months. The Eastern Pacific hurricane season is from May 15 to November 30. (Below is a graphic that shows you when hurricanes are most active across parts of the world.)

Who names hurricanes?
From 1950 to 1952, tropical cyclones of the North Atlantic Ocean were identified by the phonetic alphabet (Able-Baker-Charlie-etc.), but in 1953 the US Weather Bureau switched to women's names. The rest of the world eventually caught on, and naming rights now go by the World Meteorological Organization, which uses different sets of names depending on the part of the world the storm is in. Around the U.S., only women's names were used until 1979, when it was decided that they should alternate a list that included men's names too. There's 6 different name lists that alternate each year. If a hurricane does significant damage, its name is retired and replaced with another.
Atlantic Hurricane Names
Eastern Pacific Hurricane Names

What is the difference between a hurricane and a typhoon?
Nothing except geography. Tropical storms occur in several of the world's oceans, and except for their names, they are essentially the same type of storm. In the Atlantic Ocean, Gulf of Mexico, and the Eastern Pacific Ocean, they are called hurricanes. In the Western Pacific Ocean, they are called typhoons. In the Indian Ocean, the Bay of Bengal, and Australia, these types of storms are called cyclones.

Who are the "Hurricane Hunters"?
The brave "hurricane hunters" work for the National Oceanic and Atmospheric Administration (NOAA). Each mission lasts about ten hours, with the crews passing four to six times through the storm. The planes carry radar, sophisticated computers, and weather instruments that determine characteristics such as temperature, air pressure, wind speed, and wind direction inside the hurricane. The crews also release instruments that measure temperature, air pressure, and wind at different levels as the devices drop through the hurricane toward the ocean. By mission's end, NOAA can warn everyone in the hurricane's path. Below is a photo of the hurricane hunters taking measurements inside Hurricane Katrina.

What is coastal beach erosion?
Coastal beach erosion is the wearing away of land, the removal of beach or dune sediments by wave action, tidal currents, wave currents, or drainage. Waves are generated by storms, wind, or hurricanes and can cause coastal erosion. This may take the form of long-term losses of sediment and rocks, or merely the temporary redistribution of coastal sediments.

TROPICAL STORM WATCH - Tropical Storm conditions with sustained winds from 39 -74 mph are possible in your area within the next 36 hours.

TROPICAL STORM WARNING - Tropical Storm conditions are expected in your area within the next 24 hours.

HURRICANE WATCH - Hurricane conditions with sustained winds of 74 mph or greater are possible in your area within the next 36 hours. This WATCH should trigger your family's disaster plan, and protective measures should be initiated. Especially, those actions that require extra time such as securing a boat and leaving a barrier island.

HURRICANE WARNING - Hurricane conditions are expected in your area within 24 hours. Once this WARNING has been issued, your family should be in the process of completing protective actions and deciding the safest location to be during the storm.

COASTAL FLOOD WATCH - The possibility exists for the inundation of land areas along the coast within the next 12 to 36 hours.

COASTAL FLOOD WARNING - Land areas along the coast are expected to become, or have become, inundated by sea water above the typical tide action.

SMALL CRAFT ADVISORY - A small craft advisory is a type of warning issued by the National Weather Service, most frequently in coastal areas. It is issued when winds have reached, or are expected to reach within 12 hours, a speed marginally less than that which is considered gale force, usually 25-38 mph.

Click Here to see if there are any active warnings in your area.

Tropical Wave - A low pressure trough moving generally westward with the trade winds.

Tropical Disturbance - An organized area of thunderstorms that usually forms in the tropics. Typically, they maintain their identity for 24 hours and are accompanied by heavy rains and gusty winds.

Tropical Cyclone - A generic term for any organized low pressure that develops over tropical and sometimes sub-tropical waters. Tropical depressions, tropical storms, and hurricanes are all example of tropical cyclones.

Tropical Depression - An organized area of low pressure in which sustained winds are 38 mph or less.

Tropical Storm - A tropical cyclone with maximum sustained wind speeds that range from 39 to 73 mph.

Hurricane - A tropical cyclone with sustained winds of at least 74 mph.

To learn more about hurricanes, Click Here to watch a variety of videos teaching you the ins and outs of nature's fury. I would like to give a special thanks to Pinellas County Emergency management for putting these instructional videos together.

BEFORE A HURRICANE: Have a disaster plan and a pet plan ready. Before a storm threatens, contact your veterinarian or local humane society for information on preparing your pets for an emergency. Board up windows and bring in outdoor objects that could blow away. Make sure you know which county or parish you live in and know where all the evacuation routes are. Prepare a disaster supplies kit for your home and car. Include a first aid kit, canned food and a can opener, bottled water, battery-operated radio, flashlight, protective clothing and written instructions on how to turn off electricity, gas, and water. Have a NOAA weather radio handy with plenty of batteries, so you can listen to storm advisories. Have some cash handy as well, because following a hurricane, banks and ATMs may be temporarily closed. Make sure your car is filled with gasoline.

DURING A HURRICANE: Stay away from low-lying and flood prone areas. Always stay indoors during a hurricane, because strong winds will blow things around. Leave mobile homes and to go to a shelter. If your home isn't on higher ground, go to a shelter. If emergency managers say to evacuate, then do so immediately.

AFTER A HURRICANE: Stay indoors until it is safe to come out. Check for injured or trapped people, without putting yourself in danger. Watch out for flooding which can happen after a hurricane. Do not attempt to drive in flooding water. Stay away from standing water. It may be electrically charged from underground or downed power lines. Don't drink tap water until officials say its safe to do so.

Stay alert to storm advisories by using your NOAA weather radio.

Enact your family disaster plan.

Map out your route. Use travel routes specified by local authorities.

Do not get on the road without a place to go.

Fill your car with gasoline.

Enact your pet plan. Before a storm threatens, contact your veterinarian or local humane society for information on preparing your pets for an emergency.

Bring your disaster supply kit. Make sure you include important documents. Have enough food and water for at least 3 days. Bring flashlights for emergency lightning, since it's likely that there will be power outages and most places will be running on backup power.

Secure your home before leaving. Board up windows and glass doors, anchor loose objects or bring them inside and lock your doors.

Have some cash handy. Following a hurricane, banks and ATMs may be temporarily closed.

Notify your family and friends of your plans.

WHEN EVACUATING:

If possible, evacuate to the home of either friends or family in a non-vulnerable area within your county or parish.

Next, try a hotel.

As a last result, go to a public shelter. Remember, shelters are not designed for comfort and do not usually accept pets.

Here is a list of what what you will need for 3 to 5 days if you chose to stay at your home during a hurricane.

Drinking Water Battery-operated Weather Radio

Canned Food Portable Alarm Clock

Manual Can Opener Extra Batteries

Extra Prescription Medicine Flashlights

Eating Utensils Rope

First Aid Kit Hammer and Nails

Trash Bags Duct Tape

Cash Extension Cords

Pillows and Blankets Tarp

Sleeping Bags Mosquito Repellent

Water Jugs Cleaning Supplies

As far as tools are concerned, the following are a must. Remember, power tools may be useless for several days after a storm.

Hand Saw (8 or 10 point)

Claw Hammer

Shovel

Push Broom

Screw Drivers

Limb Saw (pruning saw)

Vice Grips

Utility Knife

Cotton Work Gloves

Lesson Plan: Here is a great lesson plan on learning about hurricane safety. In this activity, Owlie teaches kids about hurricanes and quizzes them about what they learned. Note: This is a PDF file, so you need to have Adobe Acrobat Reader.

Lesson Plan: Here is a great lesson plan on understanding hurricanes. Students will learn how wind speed increases the height and why higher waves occur in shallower water. This activity is for grades 6-8.

Lesson Plan: Here is a great lesson plan on elementary reading comprehension. This lesson contains a broader vocabulary, more hurricane facts, and more thought-provoking writing prompts. It works well for grades 3-5. Note: This is a PDF file, so you need to have Adobe Acrobat Reader.

Lesson Plan: Here is a great interactive lesson plan on allowing kids to create their very own hurricane. It lets you try to create ideal hurricane conditions by changing the winds, latitude, moisture, and sea temperature. It even keeps score! This is a great activity for 5-8th graders.

Lesson Plan: Here is a great interactive lesson plan that lets kids aim a hurricane. It lets you move the hurricane symbol, high pressure symbol and low pressure symbol to track your very own hurricane. Sometimes your hurricane will make landfall, other times it misses the U.S. all together. It lets kid understand how important the setup of weather impacts where hurricanes go.

Suck An Egg Into A Bottle Experiment: Here is an experiment that shows how pressure is created in our atmosphere by sucking an egg in a bottle. This is a very cool experiment!

Make Your Own Barometer I Experiment: Here is an experiment that allows the kids to make a barometer.

Make Your Own Barometer II Experiment: Here is an experiment that allows the kids to make a barometer.

Create Evaporation Experiment: Here is an experiment that shows kids how evaporation takes place.

Science Fair Project Ideas: Here is a complete list of science fair project ideas. Discover the science behind the weather that impacts us every day.

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What is a hurricane? A hurricane is a huge storm! It can be up to 600 miles across and have strong winds spiraling inward and upward at speeds of 75 to 200 mph. Each hurricane usually lasts for over a week, moving 10-20 miles per hour over the open ocean.

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A flood happens when too much rain falls, brought by storms and strong winds, and which can't be absorbed by the soil.

Rivers burst their banks and the water spills onto the land. Strong winds blowing across the sea make huge waves that surge onto the land and flood coastal areas.

River Floods

River floods happen when rivers and streams cannot carry away all the extra water that falls as rain or comes from melting snow.

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A flood happens when too much rain falls, brought by storms and strong winds, and which can't be absorbed by the soil. Rivers burst their banks and the water spills onto the land. Strong winds blowing across the sea make huge waves that surge onto the land and flood coastal areas.

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What is a volcano?
A volcano is a mountain that opens downward to a pool of molten rock below the surface of the earth. When pressure builds up, eruptions occur. Gases and rock shoot up through the opening and spill over or fill the air with lava fragments. Eruptions can cause lateral blasts, lava flows, hot ash flows, mudslides, avalanches, falling ash and floods. Volcano eruptions have been known to knock down entire forests. An erupting volcano can trigger tsunamis, flash floods, earthquakes, mudflows and rockfalls.

Click Here to learn more about volcanoes from USGS.

How are volcanoes formed?
Volcanoes are formed when magma from within the Earth's upper mantle works its way to the surface. At the surface, it erupts to form lava flows and ash deposits. Over time as the volcano continues to erupt, it will get bigger and bigger.

What are the different stages of volcanoes?
Scientists have categorized volcanoes into three main categories: active, dormant, and extinct. An active volcano is one which has recently erupted and there is a possibility that it may erupt soon. A dormant volcano is one which has not erupted in a long time but there is a possibility it can erupt in the future. An extinct volcano is one which has erupted thousands of years ago and there's no possibility of eruption.

Why do volcanoes erupt?
The Earth's crust is made up of huge slabs called plates, which fit together like a jigsaw puzzle. These plates sometimes move. The friction causes earthquakes and volcanic eruptions near the edges of the plates. The theory that explains this process is called plate tectonics.

What are plate tectonics?
The theory of plate tectonics is a interesting story of continents drifting from place to place breaking apart, colliding, and grinding against each other. The plate tectonic theory is supported by a wide range of evidence that considers the earth's crust and upper mantle to be composed of several large, thin, relatively rigid plates that move relative to one another. The plates are all moving in different directions and at different speeds. Sometimes the plates crash together, pull apart or sideswipe each other. When this happens, it commonly results in earthquakes.
Click Here to learn more about plate tectonics and the drifting of our continents.

How many volcanoes are there?
There are more than 1500 active volcanoes on the Earth. We currently know of 80 or more which are under the oceans. Active volcanoes in the U.S. are found mainly in Hawaii, Alaska, California, Oregon and Washington.

What is the difference between lava and magma?
Magma is liquid rock inside a volcano. Lava is liquid rock (magma) that flows out of a volcano. Fresh lava glows red hot to white hot as it flows.

Why does lava take a long time to cool down?
Lava cools slowly because lava is a poor conductor of heat. Lava flows slow down and thicken as they harden.

What is a pyroclastic flow?
A pyroclastic flow is a fluidized mixture of solid to semi-solid fragments and hot, expanding gases that flows down the sides of a volcano. These awesome features are heavier-than-air emulsions that move much like a snow avalanche, except that they are fiercely hot, contain toxic gases, and move at phenomenal, hurricane-force speeds. They are the most deadly of all volcanic phenomena.

What is lahar?
A lahar is a type of mudflow or debris flow composed of pyroclastic material, rocky debris, and water. The material flows down from a volcano, typically along a river valley. It is very dangerous because it's consistency and the way it acts is very much like cement. It is liquid when it's moving, but when it stops, it solidifies. This can cause just as much devastation as lava itself.

What is pumice?
Pumice is a light, porous volcanic rock that forms during explosive eruptions. It resembles a sponge because it consists of a network of gas bubbles frozen amidst fragile volcanic glass and minerals. All types of magma (basalt, andesite, dacite, and rhyolite) will form pumice.

What is the largest active volcano?
The world's largest, active volcano is Mauna Loa in Hawaii, where famous coffee is grown in the rich volcanic soils. Mauna Loa is 13,677 feet above sea level. From its base below sea level to its summit, Mauna Loa is taller than Mount Everest.

What is the Ring of Fire?
The Pacific Ring of Fire is an area of frequent earthquakes and volcanic eruptions encircling the basin of the Pacific Ocean. The Ring of Fire has 452 volcanoes and is home to over 50% of the world's active and dormant volcanoes. Ninety percent of the world's earthquakes and 81% of the world's largest earthquakes occur along the Ring of Fire.

What is volcanic lightning?
Volcanic lightning, also known as dirty thunderstorms, is capable of producing some of the most powerful and visually striking lightning storms on Earth. Not all volcanic eruptions produce lightning. When it does occur, a single eruption can create multiple, separate lightning storms. The lightning seems to be set off by explosions during the eruption, although not all explosions cause lightning. During recent eruptions that displayed lightning, scientists observed the most intense lightning occurred at the beginning of the eruption and gradually decreased as the eruption continued, sometimes over a period of weeks.

When is a volcano considered active?
Surprisingly, there is no consensus among volcanologists on how to define an active volcano. The lifespan of a volcano can vary from months to several million years, making such a distinction sometimes meaningless when compared to the lifespans of humans or even civilizations. For example, many of Earth's volcanoes have erupted dozens of times in the past few thousand years but are not currently showing signs of activity. Given the long lifespan of such volcanoes, they are very active. By our lifespans, however, they are not.

What is a Vulcanian Eruption?
A vulcanian eruption is a type of explosive eruption that ejects new lava fragments that do not take on a rounded shape during their flight through the air. This may be because the lava is too viscous or already solidified. These moderate-sized explosive eruptions commonly eject a large proportion of volcanic ash and also breadcrust bombs and blocks.

What is a mud volcano?
In volcanic regions, mud volcanoes are usually small volcano-shaped cones of mud. They are built as mud erupts from a vent, either as a flowing liquid or ejected into the air. The mud is formed as acid gases rise through the crust, react with rock and turn it into clay. The mud is a mixture of clay and groundwater. The mud volcanoes erupt following pressurization from geothermal steam and gases.

What is a tsunami?
A tsunami is a large ocean wave usually caused by an underwater earthquake or a volcanic explosion. Tsunamis are NOT tidal waves. Tidal waves are caused by the forces of the moon, sun, and planets upon the tides, as well as the wind as it moves over the water. With typical waves, water flows in circles, but with a tsunami, water flows straight. This is why tsunamis cause so much damage!

Click Here to see an animation of an earthquake and the resulting tsunami. It's great for kids, because they get to see how it actually happens!
Click Here to get the latest tsunami warning information from the NWS.

What is the difference between active, dormant and extinct volcanoes?

Active volcanoes - Scientists usually consider a volcano active if it is currently erupting or showing signs of unrest, such as unusual earthquake activity or significant new gas emissions. Many scientists also consider a volcano active if it has erupted in historic time. It's important to note that the span of recorded history differs from region to region; in the Mediterranean, recorded history reaches back more than 3,000 years but in the Pacific Northwest of the United States, it reaches back less than 300 years, and in Hawaii, little more than 200 years.

Dormant volcanoes - Dormant volcanoes are those that are not currently active (as defined above), but could become restless or erupt again.

Extinct volcanoes - Extinct volcanoes are those that scientists consider unlikely to erupt again. Whether a volcano is truly extinct is often difficult to determine. For example, since calderas have lifespans sometimes measured in millions of years, a caldera that hasn't produced an eruption in tens of thousands of years is likely to be considered dormant instead of extinct. Yellowstone caldera in Yellowstone National Park is at least 2 million years old and hasn't erupted for 70,000 years, yet scientists do not consider Yellowstone as extinct. In fact, because the caldera has frequent earthquakes, a very active geothermal system, and rapid rates of ground uplift, many scientists consider it to be a very active volcano.

What are the different types of volcanoes?
Volcanoes are grouped into four types: cinder cones, composite volcanoes, and shield volcanoes.

Cinder cones are circular or oval cones made up of small fragments of lava from a single vent that have been blown into the air, cooled and fallen around the vent.

Composite volcanoes which are also called 'stratovolcanoes' are steep-sided volcanoes composed of many layers of volcanic rocks, usually made from high-viscosity lava, ash and rock debris. Mt. Rainier and Mount St. Helens are examples of this type of volcano.

Shield volcanoes are volcanoes shaped like a bowl or shield in the middle with long gentle slopes made by basaltic lava flows. Basalt lava flows from these volcanoes are called flood basalts. The volcanoes that formed the basalt of the Columbia Plateau were shield volcanoes.

When did Mount St. Helens erupt?
On May 18, 1980, Mount St. Helens erupted. It's located in southwestern Washington State in the Cascade Range. The blast was heard as far away as Montana, Idaho, Canada and California. Fifty-seven people died and the eruption caused $1.2 billion in damage.

Click Here for more info on Mount St. Helens.

What are some other notable volcano eruptions?
Krakatoa was a dormant volcano in Indonesia, which awakened and produced one of the biggest volcanic eruptions in 1883. So massive was the eruption that the sound of it was heard as far away as Australia. It's widely reported as the loudest sound heard in recorded history. The Krakatoa eruption created a huge amount of ash cloud which covered the Earth and reduced global temperatures for 5 years! A total of 40,000 people died in that explosion and an entire chain of the volcanic island was destroyed. For more info: Click Here!

Mount Pelee was a dormant volcano situated in the Caribbean island of Martinique. In 1902, it erupted in a massive horizontal explosion sending huge clouds of ash released towards the nearby town of Saint-Pierre. The side of the volcano exploded and lava flowed straight into the town, killing 30,000 people in a matter of minutes. It is regarded as one of the biggest and most devastating volcanic eruptions of the 20th century, a benchmark for future eruptions.

Mount Fujiyama, also popularly known as Mount Fuji, is an active volcano which last erupted in 1708. It is incidentally the tallest mountain in Japan. If you are visiting Tokyo, the capital of Japan, look in the west on a clear day and you will be able to see Mount Fuji. It is an iconic volcano. Mount Fuji is 3,776 meters high and it is snow clad throughout the year, with five lakes surrounding it. Currently in a state of dormancy, there has not been any eruption reported for more than 300 years. The last known eruption lasted for about 3 weeks during which it covered the surrounding villages with ash and cinders. Mount Fuji is now a popular tourist location with a large number of climbers actively scaling the mountain top.

MAGMA - Magma is the liquid rock inside a volcano.

LAVA - Lava is the liquid rock (magma) that flows out of a volcano. Lava glows red hot to white hot as it flows.

ACTIVE VOLCANO - An active volcano is one that erupts regularly.

DORMANT VOLCANO - A dormant volcano is one that has not erupted for many years, although there is still some activity deep inside.

EXTINCT VOLCANO - An extinct volcano is a volcano that is no longer active.

GEYSERS - Geysers are springs that throw boiling water high in the air. They are caused by volcanic heat warming trapped ground water.

ASH - Ash are very small fragments of lava or rock blasted into the air by volcanic explosions.

PUMICE - It is a light-colored volcanic rock containing lots of bubbles from trapped gases.

BASALT - Basalt is a hard, black volcanic rock.

CALDERA - A caldera is a large, usually circular depression at the summit of a volcano formed when magma is withdrawn or erupted from a shallow underground magma reservoir.

ERUPTION CLOUD - A cloud of tephra and gases that forms downwind of an erupting volcano is called an eruption cloud.

FAULT - Faults are fractures or fracture zones in the Earth's crust along which one side moves with respect to the other. A fault scarp is a cliff or steep slope that sometimes forms along the fault at the surface.

FISSURE - On volcanoes, a fissure is an elongate fracture or crack at the surface from which lava erupts.

PILLOW LAVA - When basalts erupt underwater, they commonly form pillow lavas, which are mounds of elongate lava "pillows" formed by repeated oozing and quenching of the hot basalt.

PRYOCLASTIC FLOW - A pyroclastic flow is a ground-hugging avalanche of hot ash, pumice, rock fragments, and volcanic gas that rushes down the side of a volcano.

TEPHRA - Tephra is a general term for fragments of volcanic rock and lava regardless of size that are blasted into the air by explosions or carried upward by hot gases in eruption columns or lava fountains.

VENT - Vents are openings in the Earth's crust from which molten rock and volcanic gases escape onto the ground or into the atmosphere.

OBSIDIAN - Obsidian is dense volcanic glass, usually rhyolite in composition and typically black in color.

Click Here to see if there has been any recent volcanic activity across the U.S.

PLAN FOR A VOLCANO: First of all, have a disaster plan and know whether or not you are at risk for danger. Be prepared for mudslides, flash floods, earthquakes, ash falling, acid rain and tsunamis. Prepare a disaster supplies kit for your home and car. Include a first aid kit, canned food and a can opener, bottled water, battery-operated radio, flashlight, protective clothing, dust mask, goggles and sturdy shoes. Don't forget, know all of your evacuation routes.

DURING A VOLCANO: Follow the evacuation order issued by authorities. Avoid areas downwind and river valleys downstream of the volcano. If your caught indoors, close all windows and doors, put machinery inside a barn, and bring animals inside. If you're trapped outdoors, seek shelter indoors. If you're caught in falling rocks, roll into a ball and protect your head. If you're caught near a stream, be aware of mudflows and move to higher ground. Protect yourself when ash falls by wearing long-sleeved shirts and long pants. Use goggles to protect your eyes. Wear a dust mask and keep car engines off.

AFTER A VOLCANO: Cover you mouth and nose. Volcanic ash can irritate your respiratory system. Wear goggles and protect your eyes. Keep your skin covered. Clear roofs of ash, because the ash is very heavy and can cause the building to collapse.

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What is a volcano? A volcano is a mountain that opens downward to a pool of molten rock below the surface of the earth. When pressure builds up, eruptions occur. Gases and rock shoot up through the opening and spill over or fill the air with lava fragments.

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Volcanoes
(Volcanoes are not associated with weather, but instead are natural disasters.)

What is a volcano?
A volcano is a mountain that opens downward to a pool of molten rock below the surface of the earth. When pressure builds up, eruptions occur. Gases and rock shoot up through the opening and spill over or fill the air with lava fragments. Eruptions can cause lateral blasts, lava flows, hot ash flows, mudslides, avalanches, falling ash and floods. Volcano eruptions have been known to knock down entire forests. An erupting volcano can trigger tsunamis, flash floods, earthquakes, mudflows and rockfalls.

How are volcanoes formed?
Volcanoes are formed when magma from within the Earth's upper mantle works its way to the surface. At the surface, it erupts to form lava flows and ash deposits. Over time as the volcano continues to erupt, it will get bigger and bigger.

What are the different stages of volcanoes?
Scientists have categorized volcanoes into three main categories: active, dormant, and extinct. An active volcano is one which has recently erupted and there is a possibility that it may erupt soon. A dormant volcano is one which has not erupted in a long time but there is a possibility it can erupt in the future. An extinct volcano is one which has erupted thousands of years ago and there's no possibility of eruption.

Why do volcanoes erupt? The Earth's crust is made up of huge slabs called plates, which fit together like a jigsaw puzzle. These plates sometimes move. The friction causes earthquakes and volcanic eruptions near the edges of the plates. The theory that explains this process is called plate tectonics.

The theory of plate tectonics is a interesting story of continents drifting from place to place breaking apart, colliding, and grinding against each other. The plate tectonic theory is supported by a wide range of evidence that considers the earth's crust and upper mantle to be composed of several large, thin, relatively rigid plates that move relative to one another. The plates are all moving in different directions and at different speeds. Sometimes the plates crash together, pull apart or sideswipe each other. When this happens, it commonly results in earthquakes. What are plate tectonics?

Continental Drift: To see this animation again, just refresh this page! This animation shows you what our planet looked like millions of years ago and what it looks like now! (Graphic Credit: Geology Department at University of California, Berkeley)

There are more than 1500 active volcanoes on the Earth. We currently know of 80 or more which are under the oceans. Active volcanoes in the U.S. are found mainly in Hawaii, Alaska, California, Oregon and Washington.
How many volcanoes are there?

What are the different types of volcanoes?
Volcanoes are grouped into four types: cinder cones, composite volcanoes, shield volcanoes and lava volcanoes.

Cinder Cones

Cinder cones are circular or oval cones made up of small fragments of lava from a single vent that have been blown into the air, cooled and fallen around the vent.

Composite Volcanoes

Composite volcanoes are steep-sided volcanoes composed of many layers of volcanic rocks, usually made from high-viscosity lava, ash and rock debris. Mt. Rainier and Mount St. Helens are examples of this type of volcano.

Shield Volcanoes

Shield volcanoes are volcanoes shaped like a bowl or shield in the middle with long gentle slopes made by basaltic lava flows. Basalt lava flows from these volcanoes are called flood basalts. The volcanoes that formed the basalt of the Columbia Plateau were shield volcanoes.

Lava Volcanoes

Lava domes are formed when erupting lava is too thick to flow and makes a steep-sided mound as the lava piles up near the volcanic vent. The eruption of Mount St. Helens in 1980 was caused in part by a lava dome shifting to allow explosive gas and steam to escape from inside the mountain.

Magma is liquid rock inside a volcano. Lava is liquid rock (magma) that flows out of a volcano. Fresh lava glows red hot to white hot as it flows.

What is the difference between lava and magma?

Why does lava take a long time to cool down?
Lava cools slowly because lava is a poor conductor of heat. Lava flows slow down and thicken as they harden.
What is a pyroclastic flow?
A pyroclastic flow is a fluidized mixture of solid to semi-solid fragments and hot, expanding gases that flows down the sides of a volcano. These awesome features are heavier-than-air emulsions that move much like a snow avalanche, except that they are fiercely hot, contain toxic gases, and move at phenomenal, hurricane-force speeds. They are the most deadly of all volcanic phenomena.

What is lahar?
A lahar is a type of mudflow or debris flow composed of pyroclastic material, rocky debris, and water. The material flows down from a volcano, typically along a river valley. It is very dangerous because it's consistency and the way it acts is very much like cement. It is liquid when it's moving, but when it stops, it solidifies. This can cause just as much devastation as lava itself.
What is pumice?
Pumice is a light, porous volcanic rock that forms during explosive eruptions. It resembles a sponge because it consists of a network of gas bubbles frozen amidst fragile volcanic glass and minerals. All types of magma (basalt, andesite, dacite, and rhyolite) will form pumice.

What is the largest active volcano?
The world's largest, active volcano is Mauna Loa in Hawaii, where famous coffee is grown in the rich volcanic soils. Mauna Loa is 13,677 feet above sea level. From its base below sea level to its summit, Mauna Loa is taller than Mount Everest.

What is the Ring of Fire?

The Pacific Ring of Fire is an area of frequent earthquakes and volcanic eruptions encircling the basin of the Pacific Ocean. The Ring of Fire has 452 volcanoes and is home to over 50% of the world's active and dormant volcanoes. Ninety percent of the world's earthquakes and 81% of the world's largest earthquakes occur along the Ring of Fire.

When did Mount St. Helens erupt?
On May 18, 1980, Mount St. Helens erupted. It's located in southwestern Washington State in the Cascade Range. The blast was heard as far away as Montana, Idaho, Canada and California. Fifty-seven people died and the eruption caused $1.2 billion in damage.

What are some other notable volcano eruptions?
Krakatoa was a dormant volcano in Indonesia, which awakened and produced one of the biggest volcanic eruptions in 1883. So massive was the eruption that the sound of it was heard as far away as Australia. It's widely reported as the loudest sound heard in recorded history. The Krakatoa eruption created a huge amount of ash cloud which covered the Earth and reduced global temperatures for 5 years! A total of 40,000 people died in that explosion and an entire chain of the volcanic island was destroyed. For more info: Click Here!

Mount Pelee was a dormant volcano situated in the Caribbean island of Martinique. In 1902, it erupted in a massive horizontal explosion sending huge clouds of ash released towards the nearby town of Saint-Pierre. The side of the volcano exploded and lava flowed straight into the town, killing 30,000 people in a matter of minutes. It is regarded as one of the biggest and most devastating volcanic eruptions of the 20th century, a benchmark for future eruptions.

Mount Fujiyama, also popularly known as Mount Fuji, is an active volcano which last erupted in 1708. It is incidentally the tallest mountain in Japan. If you are visiting Tokyo, the capital of Japan, look in the west on a clear day and you will be able to see Mount Fuji. It is an iconic volcano. Mount Fuji is 3,776 meters high and it is snow clad throughout the year, with five lakes surrounding it. Currently in a state of dormancy, there has not been any eruption reported for more than 300 years. The last known eruption lasted for about 3 weeks during which it covered the surrounding villages with ash and cinders. Mount Fuji is now a popular tourist location with a large number of climbers actively scaling the mountain top.

What is a tsunami?
A tsunami is a large ocean wave usually caused by an underwater earthquake or a volcanic explosion. Tsunamis are NOT tidal waves. Tidal waves are caused by the forces of the moon, sun, and planets upon the tides, as well as the wind as it moves over the water. With typical waves, water flows in circles, but with a tsunami, water flows straight. This is why tsunamis cause so much damage!

Know the Lingo
MAGMA - Magma is the liquid rock inside a volcano.

LAVA - Lava is the liquid rock (magma) that flows out of a volcano. Lava glows red hot to white hot as it flows.

ACTIVE VOLCANO - An active volcano is one that erupts regularly.
Volcano Safety Tips
PLAN FOR A VOLCANO: First of all, have a disaster plan and know whether or not you are at risk for danger. Be prepared for mudslides, flash floods, earthquakes, ash falling, acid rain and tsunamis. Prepare a disaster supplies kit for your home and car. Include a first aid kit, canned food and a can opener, bottled water, battery-operated radio, flashlight, protective clothing, dust mask, goggles and sturdy shoes. Don't forget, know all of your evacuation routes. DURING A VOLCANO: Follow the evacuation order issued by authorities. Avoid areas downwind and river valleys downstream of the volcano. If your caught indoors, close all windows and doors, put machinery inside a barn, and bring animals inside. If you're trapped outdoors, seek shelter indoors. If you're caught in falling rocks, roll into a ball and protect your head. If you're caught near a stream, be aware of mudflows and move to higher ground. Protect yourself when ash falls by wearing long-sleeved shirts and long pants. Use goggles to protect your eyes. Wear a dust mask and keep car engines off.
DORMANT VOLCANO - A dormant volcano is one that has not erupted for many years, although there is still some activity deep inside. AFTER A VOLCANO: Cover you mouth and nose. Volcanic ash can irritate your respiratory system. Wear goggles and protect your eyes. Keep your skin covered. Clear roofs of ash, because the ash is very heavy and can cause the building to collapse.
Volcano Activities
Lesson Plan: Here are great lesson plans on learning more about volcanoes. These are great lesson plans for elementary school students.
EXTINCT VOLCANO - An extinct volcano is a volcano that is no longer active.Volcano Experiment: Here is an experiment on how to make a soda bottle volcano with Mentos.
Volcano Experiment: Here is another experiment on how to make a baking soda volcano.
GEYSERS - Geysers are springs that throw boiling water high in the air. They are caused by volcanic heat warming trapped ground water.Science Fair Project Ideas: Here is a complete list of science fair project ideas. Discover the science behind the weather that impacts us every day.

ASH - Ash are very small fragments of lava or rock blasted into the air by volcanic explosions.

PUMICE - It is a light-colored volcanic rock containing lots of bubbles from trapped gases.

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Weather Wiz Kids weather information for kids

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Weather Wiz Kids is a fun and safe website for kids about all the weather info they need to know. It contains tools for weather education, including weather games, activities, experiments, photos, a glossary and educational teaching materials for the classroom.

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(Image credit: NASA Earth Observatory)
Editor's note: The paper related to this research was originally reported by Live Science on Oct. 20, 2016, but was retracted by the journal Science on May 3. A recent investigation into the study uncovered manipulated images and falsified data, Science announced in a retraction statement. The article below remains as originally published, but the study's findings should no longer be considered valid. Original article below.
Mount Aso, one of the most active volcanoes in Japan, recently helped to stop a powerful earthquake before it subsided on its own, researchers discovered.

When a 7.1-magnitude quake struck Kumamoto, Japan, on April 16, 2016, it opened surface ruptures in a zone extending 25 miles (40 kilometers) in length. But scientists found evidence suggesting that the powerful earthquake was halted by a magma chamber under the Aso volcanic cluster, located 19 miles (30 km) from where the quake originated.

This finding provided scientists with a rare glimpse of how two geological phenomena - volcanoes and earthquakes - may interact. This topic is of particular interest in Japan, which is particularly vulnerable to both volcanoes and earthquakes. [ The 11 Biggest Volcanic Eruptions in History (Photos)]

An earthquake is a sudden release of pent-up energy in Earth's crust that has accumulated over time, generated by shifting tectonic plates. When two sides of a fault, or crack along a plate boundary, move apart or slide suddenly past each other, energy gets released. The waves of energy radiate outward from that jolt, often producing shaking on Earth's surface, according to the U.S. Geological Survey (USGS).

Japan is especially prone to earthquakes, as it lies in the Pacific Ring of Fire, a U-shaped area in the Pacific Ocean where several tectonic plates meet, and where many earthquakes are generated.

A number of volcanoes are also found in this Ring of Fire. And it was the particular interaction of the April 2016 earthquake with the Mount Aso volcano that triggered the researchers' interest in how seismic activity could be affected by the structure of volcanic clusters.

Shortly after the Kumamoto quake, the researchers visited the epicenter - the place on Earth's surface directly above where the earthquake originated - and spent 10 days investigating the ruptures left behind by the quake.
They discovered fresh ruptures that extended into Aso's caldera - a large, bowl-shaped depression at the volcano's summit - from the southwest to the northeast edge. And they abruptly ended there, at depths of 3.7 miles (6 km) below the surface.
Investigations of seismic activity deep under the caldera where the ruptures stopped indicated that there was a chamber holding magma - the same hot, fluid material called lava when it reaches Earth's surface - at that very spot,

Energy waves from the quake traveled toward Mount Aso through cool, brittle rock, the study authors wrote. But the sudden encounter with the extreme heat generated by rising magma under the volcano dispersed the energy upward and outward, sapping the strength of the quake's flow and stopping the rupture, they explained.

"This is the first case concerning the interaction between the volcano and co-seismic rupturing as we know so far," study lead author Aiming Lin told Live Science in an email.

Lin, a professor in the Department of Earth and Planetary Sciences at the Faculty and Graduate School of Science at Kyoto University in Japan, said that although this is the first reported evidence of a volcano putting a stop to an earthquake, there are other historical examples that could represent similar activity.

In 1707, ruptures generated by the Houei-Tokai-Nankai earthquake (magnitude 8.7) extended northward and eventually terminated at the western side of Mount Fuji, Lin wrote. And in 1930, the rupturing of the magnitude-7.3 North Izu earthquake was interrupted at the Hakone volcano in Izu Peninsula.

"Along this line, we are studying the interaction between the active faults - including co-seismic rupturing - and large earthquakes in Japan," Lin said.

This discovery could help researchers more accurately anticipate earthquakes' duration relative to their interaction with volcanoes, according to seismologist Gregory Beroza, deputy director of the Southern California Earthquake Center and a professor of geophysics at Stanford University.

"What it might mean for earthquakes is that magmatic systems might segment faults and, by doing so, limit the size of earthquakes in a predictable way," Beroza, who was not involved in the study, told Live Science in an email.

"This is just one earthquake, however," Beroza added. "No matter how interesting it is, or compelling it looks, it's potentially hazardous to generalize to future earthquakes."

The findings were published online today (Oct. 20) in the journal Science.
Original article on Live Science.

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Retracted Study: How a Volcano in Japan Halted an Earthquake

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(Image credit: NASA Earth Observatory) Editor's note: The paper related to this research was originally reported by Live Science on Oct. 20, 2016, but was retracted by the journal Science on May 3. A recent investigation into the study uncovered manipulated images and falsified data, Science announced in a retraction statement.

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Kids learn about the science of volcanoes including how they form mountains, lava, and magma; types such as cinder cone, composite, and shield; watch a video about volcanoes.

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Volcano facts | National Geographic Kids

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Check out these fascinating volcano facts with National Geographic Kids! What is a volcano? Why does it erupt? And where can you find the world's biggest?

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There are two main types of volcanoes: shield and composite. Shield volcanoes are usually found in the middle of tectonic plates. Islands like Hawai'i are good examples of this type of volcano. There's a hole in the middle of the plate and magma moves out and piles on top of itself, slowly building a mountain of rock. That magma comes from small tunnels which scientists call vents.

The other big type is a composite volcano. This type of volcano is usually what you think of as a volcano. It's shaped like a cone and mainly made up of ash, which has piled up and compacted over the years. You'd find these volcanoes in subduction zones like Mount Ararat in Turkey. The stuff that comes out is smaller. There's not so much lava but lots of small rocks and a lot of ash. Those rocks are called pyroclastic.

We'll start at the bottom when we look at the structure of a volcano. All of the molten rock in the asthenosphere finds weaknesses in the crust. The molten rock creates a main passageway called a central vent. As the magma rises, secondary vents develop. Those secondary ones are just smaller and branch from the main tube. At the top of the volcano, at its highest point, is a crater. Some volcanoes have something called a caldera. A caldera forms when a volcano gets hollow and then collapses on itself. A caldera could look like a large indentation on the side of the volcano or it could happen at the very top.

We already told you about the parts of a volcano. You must be wondering what happens with the lava. How does it get to the surface? All of the magma is created in the asthenosphere. The asthenosphere is the layer of molten rock just beneath the continental plates. The magma slowly rises through the lithosphere. It rises because it's hot and because of the increased pressure below. The magma slowly moves up the vents. Eventually passages called diapers are created. And behold! The lava flows from the volcano!

Just as there are multiple types of volcanoes, there are three types of lava. Silicic lava you should be able to figure out. Have you ever heard of the element silicon? Silicon is the main component of silicic lava. It's 70 percent silicon dioxide compounds. That type of lava has formed most of the continents.

The second type is mafic lava. It has the least amount of silicon dioxide compounds, less than 50 percent. It has a lot of iron and manganese compounds to make up the difference. It makes up most of the rock at the bottom of the ocean.

Last, but not least, is intermediate lava. It's in the middle in more ways than one. It has percentages of silicon substances in between silicic and mafic lava types. It is also the type of rock that makes up the edges of the continents (between the ocean floors and main continental plates). It's like the middle kid in the family.

Or search the sites for a specific topic.

Volcano Web Shorts: Debris Flows (USGS Video)

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There are two main types of volcanoes: shield and composite. Shield volcanoes are usually found in the middle of tectonic plates. Islands like Hawai'i are good examples of this type of volcano. There's a hole in the middle of the plate and magma moves out and piles on top of itself, slowly building a mountain of rock.