# data[].attributes.body
What you need to know and do before, during and after a landslide.

# data[].attributes.attachment_link.readable_text
Landslides can happen anytime in all regions of Canada. The best way to protect yourself and your family in case of a landslide is to follow these steps:

Learn and be alert to early warning signs.

Evacuate immediately if landslide is likely. If you cannot evacuate and are inside, curl into a ball and protect your head.

Prepare for secondary risks such as flooding, downed power lines, and damaged buildings.

Before

The key to staying safe is to prepare and to have an emergency plan in place.

Find out if you live in an area where landslides could potentially happen. Landslides may also be referred to as mudslides, debris flows, mudflows or debris avalanches.

Listen to local news and weather reports for any potential landslide watches and warnings in your area.

Download the Canadian Red Cross Be Ready App for instant access to information needed to prepare for different emergency situations.

Talk with your family and neighbours about what you would do during a landslide. Identify a safe place to gather.

Have practice drills with your family, so you know what to do and are prepared.

Become familiar with the land around where you live and work so that you understand your risk in different situations.

Avoid actions that could increase instability. For example, don't undercut a steep bank; don't build near the top or base of steep slopes; don't place fill on steep slopes; and don't drain swimming pools or otherwise increase water flow down steep slopes.

Learn how to recognize the signs of potential imminent landslides. This could include slope cracks, slope bulges, an unusual seepage of water on the slope, sudden changes in stream flow and small rocks falling.

Watch the patterns of storm water drainage on slopes near your home, especially where runoff water converges.

Know who to notify if you see these signs. Have municipal emergency contact numbers on hand.

Have your emergency kit ready

During

Be prepared to evacuate at a moment's notice.

If you suspect imminent danger evacuate immediately. Inform affected neighbours if you can, and contact your public works, fire or police department.

Listen for unusual sounds that might indicate moving debris, such as trees cracking or boulders knocking together.

If indoors:

Find cover in the part of the building that is the furthest from the approaching landslide.

Take shelter under a strong table or a bench.

Hold on firmly and stay put until all movement has stopped.

If outdoors:

Move quickly away from its likely path, keeping clear of embankments, trees, power lines and poles.
Stay away from the landslide area. The slope may experience additional failures for hours to days afterwards.

If you are in your car:

Watch for collapsed pavement, mud, fallen rocks and other indications of possible debris flow.

After

Continue to take precautions and listen to and follow directions from local authorities.

Listen to the radio, watch your local news channels, and/or follow your local news outlet and/or emergency officials on social media for further instructions from officials and local leaders.

Stay away from the slide area until local officials say it is safe to enter.

Look for and report broken utility lines to appropriate authorities. Reporting potential hazards will get the utilities turned off as quickly as possible, preventing further hazard and injury.

Check your home's foundation, chimney and surrounding land for damage.

Replant damaged ground as soon as possible because erosion caused by loss of ground cover can lead to flash flooding.

If you suspect your home is unsafe, do not enter. Rely on the professionals to clear your home for re-entry, if you are unsure.

# data[].attributes.attachment_link.title
Landslides: Before, During & After - Canadian Red Cross

# data[].attributes.attachment_link.description
Landslides can happen anytime in all regions of Canada. The best way to protect yourself and your family in case of a landslide is to follow these steps: Learn and be alert to early warning signs. Evacuate immediately if landslide is likely. If you cannot evacuate and are inside, curl into a ball and protect your head.

# data[].attributes.body
FAQs about landslides.

# data[].attributes.attachment_link.readable_text
What is a landslide?
A landslide is defined as the movement of a mass of rock, debris, or earth down a slope due to gravity. The materials may move by falling, toppling, sliding, spreading, or flowing.

What causes a landslide?
Almost every landslide has multiple causes. Slope movement occurs when forces acting down-slope (mainly due to gravity) exceed the strength of the earth materials that compose the slope. Landslides can be triggered by rainfall, snowmelt, changes in water level, stream erosion, changes in ground water, earthquakes, volcanic activity, disturbance by human activities, or any combination of these factors.

What are submarine landslides?
Earthquake shaking and other factors can also induce landslides underwater. These landslides are called submarine landslides. Submarine landslides sometimes cause tsunamis that damage coastal areas.

Where do landslides occur?
Landslides in the United States occur in all 50 States. The primary regions of landslide occurrence and potential are the coastal and mountainous areas of California, Oregon, and Washington, the States comprising the intermountain west, and the mountainous and hilly regions of the Eastern United States. Alaska and Hawaii also experience all types of landslides.

How fast do landslide travel?
Landslides can move slowly, (millimeters per year) or can move quickly and disastrously, as is the case with debris flows. Debris flows can travel down a hillside at speeds up to 200 miles per hour (more commonly, 30 - 50 miles per hour), depending on the slope angle, water content, volume of debris, and type of earth and debris in the flow. These flows are initiated by heavy periods of rainfall, but sometimes can happen as a result of short bursts of concentrated rainfall or other factors in susceptible areas. Burned areas charred by wildfires are particularly susceptible to debris flows, given certain soil characteristics and slope conditions.

Why study landslides?
Landslides are a serious geologic hazard. It is estimated that in the United States they cause in excess of $1 billion in damages and from about 25 to 50 deaths each year. Globally, landslides cause billions of dollars in damages and thousands of deaths and injuries each year.

Who is most at risk for landslides?
As people move into new areas of hilly or mountainous terrain, it is important to understand the nature of their potential exposure to landslide hazards, and how cities, towns, and counties can plan for land-use, engineering of new construction and infrastructure, and other measures which will reduce the costs of living with landslides. Although the physical causes of many landslides cannot be removed, geologic investigations, good engineering practices, and effective enforcement of land-use management regulations can reduce landslide hazards.

Do human activities cause landslides?
Yes, in some cases human activities can be a contributing factor in causing landslides. Many human-caused landslides can be avoided or mitigated. They are commonly a result of building roads and structures without adequate grading of slopes, of poorly planned alteration of drainage patterns, and of disturbing old landslides.

Where can I find landslide information for my area?
The USGS National Landslide Information Center (NLIC) is a part of the U.S. Geological Survey Landslide Hazards Program that collects and distributes all forms of information related to landslides. The NLIC is designed to serve landslide researchers, geotechnical practitioners engaged in landslide stabilization, and anyone else concerned in any way with landslide education, hazard, safety, and mitigation. Every state in the US has a geoscience agency and most have some landslide information. The Association of American State Geologists provides links to the State Geologist for every state.

What was the most expensive landslide to fix in the United States?
The Thistle, Utah, landslide cost in excess of $200 million dollars to fix. The landslide occurred during the spring of 1983, when unseasonably warm weather caused rapid snowmelt to saturate the slope. The landslide destroyed the railroad tracks of the Denver and Rio Grande Western Railway Company, and the adjacent Highway 89. It also flowed across the Spanish Fork River, forming a dam. The impounded river water inundated the small town of Thistle. The inhabitants of the town of Thistle, directly upstream from the landslide, were evacuated as the lake began to flood the town, and within a day the town was completely covered with water. Populations downstream from the dam were at risk because of the possible overtopping of the landslide by the lake. This could cause a catastrophic outburst of the dam with a massive flood downstream. Eventually, a drain system was engineered to drain the lake and avert the potential disaster.

How many deaths result from landslides?
An average of between 25 and 50 people are killed by landslides each year in the United States. The worldwide death toll per year due to landslides is in the thousands. Most landslide fatalities are from rock fall, debris-flows, or volcanic debris flows.

What should I know about wildfires and debris flows?
Wild land fires are inevitable in the western United States. Expansion of human development into forested areas has created a situation where wildfires can adversely affect lives and property, as can the flooding and landslides that occur in the aftermath of the fires. There is a need to develop tools and methods to identify and quantify the potential hazards posed by landslides produced from burned watersheds. Post-fire landslide hazards include fast-moving, highly destructive debris flows that can occur in the years immediately after wildfires in response to high intensity rainfall events, and those flows that are generated over longer time periods accompanied by root decay and loss of soil strength. Post-fire debris flows are particularly hazardous because they can occur with little warning, can exert great impulsive loads on objects in their paths, and can strip vegetation, block drainage ways, damage structures, and endanger human life. Wildfires could potentially result in the destabilization of pre-existing deep-seated landslides over long time periods.

How do landslides cause tsunamis?
Tsunamis are large, potentially deadly and destructive sea waves, most of which are formed as a result of submarine earthquakes. They may also result from the eruption or collapse of island or coastal volcanoes and the formation of giant landslides on marine margins. These landslides, in turn, are often triggered by earthquakes. Tsunamis can be generated on impact as a rapidly moving landslide mass enters the water or as water displaces behind and ahead of a rapidly moving underwater landslide.

What are some examples of landslides that have caused tsunamis?
The 1964 Alaska earthquake caused 115 deaths in Alaska alone, with 106 of those due to tsunamis generated by tectonic uplift of the sea floor, and by localized subareal and submarine landslides. The earthquake shaking caused at least 5 local slide-generated tsunamis within minutes after the shaking began. An eyewitness account of the tsunami caused by the movement and landslides of the 1964 Alaska earthquake.

Research in the Canary Islands concludes that there have been at least five massive volcano landslides that occurred in the past, and that similar large events may occur in the future. Giant landslides have the potential of generating large tsunami waves at close and also very great distances and would have the potential to devastate large areas of coastal land as far away as the eastern seaboard of North America.

Rock falls and rock avalanches in coastal inlets, such as those that have occurred in the past at Tidal Inlet, Glacier Bay National Park, Alaska, have the potential to cause regional tsunamis that pose a hazard to coastal ecosystems and human settlements. On July 9, 1958, a magnitude M 7.9 earthquake on the Fairweather Fault triggered a rock avalanche at the head of Lituya Bay, Alaska. The landslide generated a wave that ran up 524 m on the opposite shore and sent a 30-m high wave through Lituya Bay, sinking two of three fishing boats and killing two persons.

How soon does the danger of landslides end after the rain stops?
It's not possible to exactly predict the number of days or weeks that landslides remain a danger after heavy rain. Residents near mountain slopes, canyons, and landslide prone areas should stay alert even after heavy rain subsides.

Why is southern California vulnerable to landslides?
Areas that have been burned by recent wildfires are highly susceptible to debris-flow activity that can be triggered by significantly less rainfall than that which triggers debris flows from unburned hill slopes.

What was the biggest landslide in the world?
The world's biggest historic landslide occurred during the 1980 eruption of Mount St. Helens, a volcano in the Cascade Mountain Range in the State of Washington, USA. The volume of material was 2.8 cubic kilometers (km).

What was the biggest prehistoric landslide?
The world's biggest prehistoric landslide, discovered so far on land, is in southwestern Iran, and is named the Saidmarreh landslide. The landslide is located on the Kabir Kuh anticline in Southwest Iran at 33 degrees north latitude, 47.65 degrees east longitude. The landslide has a volume of about 20 cubic kilometers, a depth of 300 m, a travel distance of 14 km and a width of 5 km. This means that about 50 billion tons of rock moved in this single event!

Rotational slide: This is a slide in which the surface of rupture is curved concavely upward and the slide movement is roughly rotational about an axis that is parallel to the ground surface and transverse across the slide.

Translational slide: In this type of slide, the landslide mass moves along a roughly planar surface with little rotation or backward tilting.

Block slide: is a translational slide in which the moving mass consists of a single unit or a few closely related units that move downslope as a relatively coherent mass.

Fall: Falls are abrupt movements of masses of geologic materials, such as rocks and boulders, that become detached from steep slopes or cliffs. Separation occurs along discontinuities such as fractures, joints, and bedding planes, and movement occurs by free-fall, bouncing, and rolling. Falls are strongly influenced by gravity, mechanical weathering, and the presence of interstitial water.

Topple: Toppling failures are distinguished by the forward rotation of a unit or units about some pivotal point, below or low in the unit, under the actions of gravity and forces exerted by adjacent units or by fluids in cracks.

Debris flow: A debris flow is a form of rapid mass movement in which a combination of loose soil, rock, organic matter, air, and water mobilize as a slurry that flows downslope. Debris flows include less than 50% fines. Debris flows are commonly caused by intense surface-water flow, due to heavy precipitation or rapid snowmelt, that erodes and mobilizes loose soil or rock on steep slopes. Debris flows also commonly mobilize from other types of landslides that occur on steep slopes, are nearly saturated, and consist of a large proportion of silt- and sand-sized material. Debris-flow source areas are often associated with steep gullies, and debris-flow deposits are usually indicated by the presence of debris fans at the mouths of gullies. Fires that denude slopes of vegetation intensify the susceptibility of slopes to debris flows.

Debris avalanche: This is a variety of very rapid to extremely rapid debris flow.

Earthflow: Earthflows have a characteristic "hourglass" shape. The slope material liquefies and runs out, forming a bowl or depression at the head. The flow itself is elongate and usually occurs in fine-grained materials or clay-bearing rocks on moderate slopes and under saturated conditions. However, dry flows of granular material are also possible.
Mudflow: A mudflow is an earthflow consisting of material that is wet enough to flow rapidly and that contains at least 50 percent sand-, silt-, and clay-sized particles. In some instances, for example in many newspaper reports, mudflows and debris flows are commonly referred to as "mudslides."

Creep: Creep is the imperceptibly slow, steady, downward movement of slope-forming soil or rock. Movement is caused by shear stress sufficient to produce permanent deformation, but too small to produce shear failure. There are generally three types of creep: (1) seasonal, where movement is within the depth of soil affected by seasonal changes in soil moisture and soil temperature; (2) continuous, where shear stress continuously exceeds the strength of the material; and (3) progressive, where slopes are reaching the point of failure as other types of mass movements. Creep is indicated by curved tree trunks, bent fences or retaining walls, tilted poles or fences, and small soil ripples or ridges.

Lateral Spreads: Lateral spreads are distinctive because they usually occur on very gentle slopes or flat terrain. The dominant mode of movement is lateral extension accompanied by shear or tensile fractures. The failure is caused by liquefaction, the process whereby saturated, loose, cohesionless sediments (usually sands and silts) are transformed from a solid into a liquefied state. Failure is usually triggered by rapid ground motion, such as that experienced during an earthquake, but can also be artificially induced. When coherent material, either bedrock or soil, rests on materials that liquefy, the upper units may undergo fracturing and extension and may then subside, translate, rotate, disintegrate, or liquefy and flow. Lateral spreading in fine-grained materials on shallow slopes is usually progressive. The failure starts suddenly in a small area and spreads rapidly. Often the initial failure is a slump, but in some materials movement occurs for no apparent reason. Combination of two or more of the above types is known as a complex landslide.

SLIDES: Although many types of mass movements are included in the general term "landslide," the more restrictive use of the term refers only to mass movements, where there is a distinct zone of weakness that separates the slide material from more stable underlying material. The two major types of slides are rotational slides and translational slides.

FLOWS: There are five basic categories of flows that differ from one another in fundamental ways. Although there are multiple types of causes of landslides, the three that cause most of the damaging landslides around the world are these:

Landslides and Water: Slope saturation by water is a primary cause of landslides. This effect can occur in the form of intense rainfall, snowmelt, changes in ground-water levels, and waterlevel changes along coastlines, earth dams, and the banks of lakes, reservoirs, canals, and rivers. Landsliding and flooding are closely allied because both are related to precipitation, runoff, and the saturation of ground by water. In addition, debris flows and mudflows usually occur in small, steep stream channels and often are mistaken for floods; in fact, these two events often occur simultaneously in the same area. Landslides can cause flooding by forming landslide dams that block valleys and stream channels, allowing large amounts of water to back up. This causes backwater flooding and, if the dam fails, subsequent downstream flooding. Also, solid landslide debris can "bulk" or add volume and density to otherwise normal streamflow or cause channel blockages and diversions creating flood conditions or localized erosion. Landslides can also cause overtopping of reservoirs and/or reduced capacity of reservoirs to store water.

Landslides and Seismic Activity: Many mountainous areas that are vulnerable to landslides have also experienced at least moderate rates of earthquake occurrence in recorded times. The occurrence of earthquakes in steep landslide-prone areas greatly increases the likelihood that landslides will occur, due to ground shaking alone or shaking- caused dilation of soil materials, which allows rapid infiltration of water. The 1964 Great Alaska Earthquake caused widespread landsliding and other ground failure, which caused most of the monetary loss due to the earthquake. Other areas of the United States, such as California and the Puget Sound region in Washington, have experienced slides, lateral spreading, and other types of ground failure due to moderate to large earthquakes. Widespread rockfalls also are caused by loosening of rocks as a result of ground shaking. Worldwide, landslides caused by earthquakes kill people and damage structures at higher rates than in the United States.

Landslides and Volcanic Activity: Landslides due to volcanic activity are some of the most devastating types. Volcanic lava may melt snow at a rapid rate, causing a deluge of rock, soil, ash, and water that accelerates rapidly on the steep slopes of volcanoes, devastating anything in its path. These volcanic debris flows (also known as lahars) reach great distances, once they leave the flanks of the volcano, and can damage structures in flat areas surrounding the volcanoes. The 1980 eruption of Mount St. Helens, in Washington triggered a massive landslide on the north flank of the volcano, the largest landslide in recorded times.

Landslide Mitigation - How to Reduce the Effects of Landslides: Vulnerability to landslide hazards is a function of location, type of human activity, use, and frequency of landslide events. The effects of landslides on people and structures can be lessened by total avoidance of landslide hazard areas or by restricting, prohibiting, or imposing conditions on hazard-zone activity. Local governments can reduce landslide effects through land-use policies and regulations. Individuals can reduce their exposure to hazards by educating themselves on the past hazard history of a site and by making inquiries to planning and engineering departments of local governments. They can also obtain the professional services of an engineering geologist, a geotechnical engineer, or a civil engineer, who can properly evaluate the hazard potential of a site, built or unbuilt.

The hazard from landslides can be reduced by avoiding construction on steep slopes and existing landslides, or by stabilizing the slopes. Stability increases when groundwater is prevented from rising in the landslide mass by (1) covering the landslide with an impermeable membrane, (2) directing surface water away from the landslide, (3) draining groundwater away from the landslide, and (4) minimizing surface irrigation. Slope stability is also increased when a retaining structure and/ or the weight of a soil/rock berm are placed at the toe of the landslide or when mass is removed from the top of the slope.

LANDSLIDE ADVISORY - a general statement about the potential of landslide activity in a given region relative to developing rainfall predictions. An advisory may include general statements about rainfall conditions that can lead to debris-flow activity, and list precautions to be taken in the event of heavy rainfall.

LANDSLIDE WATCH - means that landslide-activity will be possible, but is not imminent. People in, or planning to travel through, a watch area should check preparedness and stay informed about developing weather patterns.

LANDSLIDE WARNING - indicates that landslide activity is presently occurring and extreme caution should be taken.

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.

DEBRIS - The scattered remains of something broken or destroyed; rubble or wreckage.

DEBRIS FLOW - A churning, water-saturated mass of rock, soil and organic matter that rushes down mountain slopes, typically originating as a landslide.

GRAVITY - The natural force of attraction exerted by a celestial body, such as Earth, upon objects at or near its surface, tending to draw them toward the center of the body.

FRICTION - Force that resists the relative motion or tendency to such motion of two bodies in contact.

TRIGGER - An event that initiates a landslide.

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

BEFORE A LANDSLIDE: Avoid building near steep slopes, close to mountain edges, near drainage ways, or natural erosion valleys. Get a ground assessment of your property. Landslides occur where they have before, and in identifiable hazard locations. Ask for information on landslides in your area, specific information on areas vulnerable to landslides, and request a professional referral for a very detailed site analysis of your property, and corrective measures you can take, if necessary. Watch the patterns of storm-water drainage near your home, and note the places where runoff water converges, increasing flow in channels. These are areas to avoid during a storm. Make evacuation plans. Plan at least two evacuation routes since roads may become blocked or closed. Develop your own emergency plan for your family or business.

MINIMIZE HOME HAZARDS: Have flexible pipe fittings installed to avoid gas or water leaks, as flexible fittings are more resistant to breakage. Plant ground cover on slopes and build retaining walls. In mudflow areas, build channels or deflection walls to direct the flow around buildings. Remember: If you build walls to divert debris flow and the flow lands on a neighbor's property, you may be liable for damages. Design and construction of walls and channels strong enough to resist or divert landslides is highly specialized work, best done by qualified professionals.

DURING A STORM/LANDSLIDE: Stay alert and awake. Many debris-flow fatalities occur when people are sleeping. Listen to a NOAA Weather Radio or portable, battery-powered radio or television for warnings of intense rainfall. Be aware that intense, short bursts of rain may be particularly dangerous, especially after longer periods of heavy rainfall and damp weather. If you are in areas susceptible to landslides and debris flows, consider leaving if it is safe to do so. Remember that driving during an intense storm can be hazardous. If you remain at home, move to a second story if possible. Staying out of the path of a landslide or debris flow saves lives. Listen for any unusual sounds that might indicate moving debris, such as trees cracking or boulders knocking together. A trickle of flowing or falling mud or debris may precede larger landslides. Moving debris can flow quickly and sometimes without warning. If you are near a stream or channel, be alert for any sudden increase or decrease in water flow and for a change from clear to muddy water. Such changes may indicate landslide activity upstream, so be prepared to move quickly. Don't delay! Save yourself, not your belongings. Be especially alert when driving. Bridges may be washed out, and culverts overtopped. Do not cross flooding streams...Turn Around, Don't Drown! Embankments along roadsides are particularly susceptible to landslides. Watch the road for collapsed pavement, mud, fallen rocks, and other indications of possible debris flows. Be aware that strong shaking from earthquakes can induce or intensify the effects of landslides.

AFTER A LANDSLIDE: Stay away from the slide area. There may be danger of additional slides. Check for injured and trapped persons near the slide area. Give first aid if trained. Remember to help your neighbors who may require special assistance-infants, elderly people, and people with disabilities. Listen to a battery-operated radio or television for the latest emergency information. Remember that flooding may occur after a mudflow or a landslide. Check for damaged utility lines. Report any damage to the utility company. Check the building foundation, chimney, and surrounding land for damage. Replant damaged ground as soon as possible since erosion caused by loss of ground cover can lead to flash flooding. Seek the advice of geotechnical expert for evaluating landslide hazards or designing corrective techniques to reduce landslide risk.

Lesson Plan: Here is a great lesson plan on erosion and landslides.

Lesson Plan: Here is a great lesson plan on landslides for grades 6-8.

Lesson Plan: This lesson consists of landslides, liquefaction, and structural failure caused by earthquakes.

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.

# data[].attributes.attachment_link.description
What is a landslide? A landslide is defined as the movement of a mass of rock, debris, or earth down a slope due to gravity. The materials may move by falling, toppling, sliding, spreading, or flowing. What causes a landslide? Almost every landslide has multiple causes.

# data[].attributes.body
Fun facts about hurricanes

# data[].attributes.attachment_link.readable_text
Hurricane Facts For Kids

Enjoy our fun hurricane facts for kids. Learn a range of interesting information about tropical storms, understand how they work, where they form, the difference between hurricanes, cyclones and typhoons, how much damage Hurricane Katrina caused and much more. Read on and learn about hurricanes with our wide range of facts and trivia.

A hurricane is an intense tropical storm with powerful winds and heavy rain.

Other names for a hurricane include cyclone, typhoon and tropical storm.

While they are essentially the same thing, the different names usually indicate where the storm took place. Tropical storms that form in the Atlantic or Northeast Pacific (near the United States) are called hurricanes, those that form near in the Northwest Pacific (near Japan) are called typhoons and those that form in the South Pacific or Indian oceans are called cyclones.

Hurricanes usually form in tropical areas of the world.

Hurricanes develop over warm water and use it as an energy source.

Hurricanes lose strength as they move over land.

Coastal regions are most at danger from hurricanes.

As well as violent winds and heavy rain, hurricanes can also create tornadoes, high waves and widespread flooding.

Hurricanes are regions of low atmospheric pressure (also known as a depression).

The wind flow of hurricanes in the southern hemisphere is clockwise while the wind flow of hurricanes in the northern hemisphere is counterclockwise.

Weather in the eye of a hurricane is usually calm.

The eye of a hurricane can be anywhere from 2 miles (3.2 kilometres) in diameter to over 200 miles (320 kilometres) but they are usually around 30 miles (48 kilometres).

The winds around the eye of a hurricane are usually the strongest.

Hurricanes can be tracked by weather satellites and weather radar closer to land.

Hurricanes have led to the death of around 2 million people over the last 200 years.

The 1970 Bhola Cyclone that struck Bangladesh killed over 300000 people.

In 2005 Hurricane Katrina killed over 1800 people in the United States and caused around $80 billion dollars worth of property damage. The city of New Orleans was hit particularly hard with levee breaches leading to around 80% of the city being flooded.

# data[].attributes.attachment_link.title
Fun Hurricane Facts for Kids - Interesting Information about Cyclones & Typhoons

# data[].attributes.attachment_link.description
Hurricane Facts For Kids Enjoy our fun hurricane facts for kids. Learn a range of interesting information about tropical storms, understand how they work, where they form, the difference between hurricanes, cyclones and typhoons, how much damage Hurricane Katrina caused and much more. Read on and learn about hurricanes with our wide range of facts and trivia.

# data[].attributes.body
Everything you need to know about hurricanes.

# data[].attributes.attachment_link.readable_text
Satellite image of Category 5 Hurricane Katrina from 2005. (Wikimedia)

You've probably been hearing a lot about hurricanes lately, and you might just have some questions about these powerful storms. Here are some answers that might help explain what's happening and why.

What's a hurricane?

Hurricanes can be so strong that they create storm surges (a rising of the sea) which can pick up big objects like these boats, and put them down in places they shouldn't be, like the highway. Southern Louisiana during hurricane Katrina. (Wikimedia/FEMA/Jocelyn Augustino)

Hurricanes are really, really huge storms - hurricane Sandy in 2012 was 1,520 kilometres in diameter! They start out over the warm ocean water, rotating around an eye, which is the centre of the storm and the calmest part. As hurricanes rotate, they gather heat and energy from the warm ocean water and can spiral anywhere from 119 kilometres per hour to 321 kilometres per hour. As they travel slowly across the ocean, they get bigger until they encounter land.

Why are they called hurricanes?

Tropical storm Francis in 2006, just before it became a hurricane. Taken off a US Navy fuel ship. Just minutes after this photo, the waves were close to 3 metres high. (Photo by Stacey licensed CC BY NC-ND 2.0)

The Spanish explorers picked up the word from the indigenous people of the Caribbean in the 16th century. The Spanish word huracán was taken from the name of their storm god Juracán. It eventually became hurricane in English.

How are hurricanes named?

Category 2 Hurricane Edouard several hundred kilometres off the coast of Bermuda, as seen from the International Space Station in 2014. The dark spot in the middle is the "eye" of the hurricane. (NASA/JPL/Alex Gerst)

There are several hurricane warning centres around the world that assign hurricane names on behalf of the World Meteorological Organization. They have six different lists of names they use. If a hurricane really does a lot of damage, like hurricane Katrina did in 2005, that name is never used again. The hurricanes are named alphabetically (Arlene, Bret, Cindy...) and there are no names starting with the letters Q, U, X, Y or Z for the Atlantic hurricanes or Q and U for the Eastern North Pacific hurricanes.

How do they measure a hurricane?

A man removes debris from his yard in Florida after Hurricane Charley, a Category 4 hurricane, lifted the roof off the school across the street and dropped it in his backyard. (Wikimedia/FEMA/George Armstrong)

Once a tropical storm hits 119 kilometres per hour, it's considered a full blown hurricane. Hurricanes are measured into five categories by different criteria, including how fast they're rotating, how big the waves will be from the sea rising (known as the storm surge) and how much damage they can do. A Category 1 hurricane is the lowest and does the least damage, while a Category 5 hurricane is the worst and can do the most damage with winds over 249 kilometres per hour. Hurricane Harvey that hit Houston in August 2017 was considered a Category 4 hurricane.

Can we get hurricanes in Canada?

Damage left to the entrance to the public gardens in Halifax by Hurricane Juan, a Category 2 hurricane, in 2003. (Wikimedia/Thorfinn Stainforth/CC BY-SA 2.0 CA)

Since you need warm ocean water and a tropical atmosphere for hurricanes to form, there usually aren't any in Canada. However, that doesn't mean that a hurricane that's started down in the Caribbean can't be powerful enough to make its way up the coast and affect the Maritime provinces or British Columbia. They can still cause damage from wind, rain and waves. In 2012, Hurricane Sandy started in the Caribbean and moved up the east coast before finishing up all the way over in Ontario.

Safety tips

During Hurricane Charley in 2004, the Sarasota Mennonites provided free hot food to residents affected by the hurricane. (Wikimedia/FEMA/Mark Wolfe)

If you live in a location that is known to have hurricanes or if you're visiting a location that is in the path of a hurricane, here are some things you can do to keep safe:

Before a hurricane, help your family prepare an emergency supply kit for your home or car with a first aid kit, canned food, can opener, bottled water, battery-operated radio, flashlight and protective clothing. Make sure you know where to find your kit.

Before a hurricane, help your family put together an emergency plan for you and your pets. Your family emergency plan should include knowing the safe exits from your home and having a meeting place for your family. You can find out from your local vet or humane society how you can get your pets ready for an emergency.

During a hurricane, you and your family should follow all instructions from your local authorities. They may tell you to evacuate and go to a shelter. It's important to be safe. You can go back when the storm is over.

After a hurricane, it might take some time to get back to your home and your school. Don't worry, there will be lots of people around to help you and your family have something to eat, somewhere to sleep, get clean clothes, take care of your pets and get you back home safely.

# data[].attributes.attachment_link.title
Everything you need to know about hurricanes | CBC Kids

# data[].attributes.attachment_link.description
Satellite image of Category 5 Hurricane Katrina from 2005. (Wikimedia) You've probably been hearing a lot about hurricanes lately, and you might just have some questions about these powerful storms. Here are some answers that might help explain what's happening and why.

# data[].attributes.body
Why do Tidal Waves happen?

# data[].attributes.attachment_link.readable_text
Tides are the daily rise and fall of sea level at any given place. The pull of the Moon's gravity on Earth is the primarily cause of tides and the pull of the Sun's gravity on Earth is the secondary cause. The Moon has a greater effect because, although it is much smaller than the Sun, it is much closer. The Moon's pull is about twice that of the Sun's.

Daily Tide Patterns

To understand the tides it is easiest to start with the effect of the Moon on Earth. As the Moon revolves around our planet, its gravity pulls Earth toward it. The lithosphere is unable to move much but the water above it is pulled by the gravity and a bulge is created. This bulge is the high tide beneath the Moon. The Moon's gravity then pulls the Earth toward it, leaving the water on the opposite side of the planet behind. This creates a second high tide bulge on the opposite side of Earth from the Moon. These two water bulges on opposite sides of the Earth aligned with the Moon are the high tides. Click here to learn more.Since so much water is pulled into the two high tides, low tides form between the two high tides. As the Earth rotates beneath the Moon, a single spot will experience two high tides and two low tides every day.The tidal range is the difference between the ocean level at high tide and the ocean at low tide. The tidal range in a location depends on a number of factors, including the slope of the seafloor. Water appears to move a greater distance on a gentle slope than on a steep slope.

Monthly Tidal Patterns

Waves are additive so when the gravitational pull of the Sun and Moon are in the same direction, the high tides add and the low tides add. Highs are higher and lows are lower than at other times through the month. These more extreme tides, with a greater tidal range, are called spring tides. Spring tides don't just occur in the spring; they occur whenever the Moon is in a new-moon or full-moon phase, about every 14 days. The National Oceanic and Atmospheric Administration (NOAA) has a simple diagram of this process.

Neap tides are tides that have the smallest tidal range, and they occur when the Earth, the Moon, and the Sun form a 90 degree angle. They occur exactly halfway between the spring tides, when the Moon is at first or last quarter. How do the tides add up to create neap tides? The Moon's high tide occurs in the same place as the Sun's low tide and the Moon's low tide in the same place as the Sun's high tide. At neap tides, the tidal range relatively small. Here is another simple animation of spring and neap tides from NOAA.High tides occur about twice a day, about every 12 hours and 25 minutes. The reason is that the Moon takes 24 hours and 50 minutes to rotate once around the Earth so the Moon is over the same location 24 hours and 50 minutes later. Since high tides occur twice a day, one arrives each 12 hours and 25 minutes. What is the time between a high tide and the next low tide? This animation shows the effect of the Moon and Sun on the tides.

Some coastal areas do not follow this pattern at all. These coastal areas may have one high and one low tide per day or a different amount of time between two high tides. These differences are often because of local conditions, such as the shape of the coastline that the tide is entering.

# data[].attributes.attachment_link.description
Tides are the daily rise and fall of sea level at any given place. The pull of the Moon's gravity on Earth is the primarily cause of tides and the pull of the Sun's gravity on Earth is the secondary cause.

# data[].attributes.body
What is a tidal wave>

# data[].attributes.attachment_link.keywords[]
national oceanic and atmospheric administration

# data[].attributes.attachment_link.description
A tidal wave is a shallow water wave caused by the gravitational interactions between the Sun, Moon, and Earth. The term "tidal wave" is often used to refer to tsunamis; however, this reference is incorrect as tsunamis have nothing to do with tides.

# data[].attributes.body
Find out what to do to prepare for an avalanche and what to do if you get stuck in one.

# data[].attributes.attachment_link.keywords[]
emergency preparedness planning how to prepare natural disaster avalanche facts safety what to do during mountain snow collapse

# data[].attributes.body
National Geographic facts about avalanches.

# data[].attributes.attachment_link.readable_text
Falling masses of snow and ice, avalanches pose a threat to anyone on snowy mountainsides. Beautiful to witness from afar, they can be deadly because of their intensity and seeming unpredictability.

Humans trigger 90 percent of avalanche disasters, with as many as 40 deaths in North America each year. Most are climbers, skiers, and snowmobilers. Learning about avalanches, and the conditions that cause them, can help people recreate more safely in the backcountry.

Types of avalanches

The recipe for an avalanche may seem simple: a mountain slope and a thick layer of snow. But Simon Trautman, an avalanche specialist at the U.S. Forest Service's National Avalanche Center and Northwest Avalanche Center in Washington, says it's actually a trifecta that causes avalanches: terrain, snowpack, and weather conditions. Avalanches do occur naturally, but when you add humans into the mix, they can be deadly, says Trautman.

Avalanches come in many shapes and sizes. Many are small slides of powdery snow that move as a formless mass downslope. Outdoor recreationists often trigger these small "sluffs," as well as more medium-sized avalanches.

Disastrous avalanches occur when massive slabs of snow break loose from a mountainside. The mass of snow shatters like broken glass as it races downhill. These hazards can travel as fast as cars on a freeway, up to 100 miles per hour, says Trautman.

Snow slides can start on mountain slopes with at least a 30-degree incline, but they occur most frequently on slopes of 35-50 degrees. Although avalanches need a slope to start, large avalanches accelerate downhill with sufficient momentum to cross flat terrain for short distances.

In some cases, a large chunk of ice or small glacier breaks off a mountainside, gathering snow and momentum and rushing down in a dangerous steamroll. One of the most deadly avalanches on Mount Everest, which killed 16 Sherpas, occurred when an ice mass the weight of 657 buses plummeted down on top of hikers.

Features of avalanches

Avalanches contain three main features: the starting zone, the avalanche track, and the runout zone. Avalanches launch from the starting zone. That's often the most unstable part of the stope, and generally higher on the mountain.

Once the avalanche starts to slide, it continues down the avalanche track, the natural path it follows downhill. After avalanches, large clearings or missing chutes of trees provide clues to an avalanche's trajectory.

The avalanche finally comes to a stop at the bottom of a slope, in the runout zone, where the snow and debris pile up.

What conditions cause an avalanche?

Avalanches are most common during the winter, December to April in the Northern Hemisphere, but they do occur year-round.

To get an avalanche, you need a surface bed of snow, a weaker layer that can collapse, and an overlaying snow slab. The highest risk period is during and immediately after a snow storm. Underlying snowpack, overloaded by a quick deluge of snow, can cause a weak layer beneath the slab to fracture naturally.

Human-triggered avalanches start when somebody walks or rides over a slab with an underlying weak layer. The weak layer collapses, causing the overlaying mass of snow to fracture and start to slide. Earthquakes can also trigger strong avalanches.

By digging a snow pit or profile, scientists can look at the composition of different snow layers that formed during a season, sort of like looking at the layers of a cake. The size and shape of the snowflakes in each layer provide clues about the weather events that occurred: big dumps of snow, drought, rain, a hard freeze, or loose, powdery snow. Larger, looser snow crystals are weaker, because there are fewer points they can touch to interact with the other snow layers. The interaction of the snow layers can help predict the chances of an avalanche.

"Snow is an incredibly dynamic and complicated medium, which means avalanches are the same," says Trautman. He emphasizes that conditions can change rapidly with the weather, and this can be deadly.

Slopes shaded from direct sun stay cooler, preventing bonding between snow layers and leading to more avalanches in cold conditions. Conversely, during the spring, sunny mountainsides have a higher risk for avalanches because of rapid warming and melting. The number of "wet snow" slides could increase in the future with climate change, experts warn.

Precipitation type and intensity, temperature, wind, slope steepness and orientation (the direction it faces), terrain, vegetation, and general snowpack conditions can influence whether and how snow moves down a slope. Moving across the terrain, slight changes in slope or how the mountainside is oriented towards the sun can create drastically different conditions.

Take avalanche danger seriously

The Forest Service runs 14 backcountry avalanche centers in the United States to provide information for people recreating in snowy wilderness areas. Forecasters use four main elements to describe conditions, assign a danger level, and help recreators make the best decisions in the backcountry.

Field teams at avalanche centers document the snowpack-the thickness and type of snow layers-and combine those data with weather conditions to estimate danger levels. The forecasts take into account the potential type and size of an avalanche, the likelihood it will occur, and the location.

In some instances, forest rangers can blast cannons and other military artillery at unstable snowpack to trigger avalanches in a safe and controlled manner-when people aren't present.

Before entering the backcountry, check online forecasts for the danger level in that area. Each mountain range has unique snow properties and therefore, avalanche risks, so checking your specific region is critical. New Zealand, Canada, and Europe also maintain year-round forecasts of avalanche danger for specific peaks and wilderness areas.

Experts recommend hiking and travelling earlier in the day. Weather conditions can change rapidly, and warming during the day creates more unstable snowpack with a higher risk for avalanches.

Education and proper training on avalanches can help prepare you. Heed all warnings and signs. Some accidents have been traced to people avoiding warnings due to psychological traps, like desiring the ultimate ski slope, untouched by humans.

Constant vigilance when you are outside can help avoid causing or getting swept up in avalanches, but even trained experts can be become victims. Be aware of the weather and terrain, and know your comfort level before you embark on an adventure. ( Read more about avalanche safety tips.)

If caught in an avalanche, try to get off the slab. In best case scenarios, this is difficult. Skiers and snowboarders can head at a 45-degree angle downhill to gather speed and veer left or right out of the slide path. Snowmobilers can punch the throttle to power out of harm's way.

No escape? Reach for a tree. No tree? Swim hard. The human body is denser than avalanche debris and will sink quickly. As the slide slows, clear air space to breathe. Then punch a hand skyward.

Once the avalanche stops, it settles like concrete, making body movement nearly impossible. Wait-and hope-for a rescue. ( Read about rescue dogs, trained to locate and dig out avalanche victims.)

"Learning about avalanches really helps people decide when and where, and how to recreate," said Trautman. "We shouldn't all be terrified of this stuff, but we should take it seriously. It's supposed to be fun!"

# data[].attributes.attachment_link.description
Falling masses of snow and ice, avalanches pose a threat to anyone on snowy mountainsides. Beautiful to witness from afar, they can be deadly because of their intensity and seeming unpredictability. Humans trigger 90 percent of avalanche disasters, with as many as 40 deaths in North America each year.

# data[].attributes.body
National Geographic facts about lightning.

# data[].attributes.attachment_link.readable_text
Lightning is an electrical discharge caused by imbalances between storm clouds and the ground, or within the clouds themselves. Most lightning occurs within the clouds.

"Sheet lightning" describes a distant bolt that lights up an entire cloud base. Other visible bolts may appear as bead, ribbon, or rocket lightning.

During a storm, colliding particles of rain, ice, or snow inside storm clouds increase the imbalance between storm clouds and the ground, and often negatively charge the lower reaches of storm clouds. Objects on the ground, like steeples, trees, and the Earth itself, become positively charged-creating an imbalance that nature seeks to remedy by passing current between the two charges.

Lightning is extremely hot-a flash can heat the air around it to temperatures five times hotter than the sun's surface. This heat causes surrounding air to rapidly expand and vibrate, which creates the pealing thunder we hear a short time after seeing a lightning flash.

Types of Lightning

Cloud-to-ground lightning bolts are a common phenomenon-about 100 strike Earth's surface every single second-yet their power is extraordinary. Each bolt can contain up to one billion volts of electricity.

A typical cloud-to-ground lightning bolt begins when a step-like series of negative charges, called a stepped leader, races downward from the bottom of a storm cloud toward the Earth along a channel at about 200,000 mph (300,000 kph). Each of these segments is about 150 feet (46 meters) long.

When the lowermost step comes within 150 feet (46 meters) of a positively charged object, it is met by a climbing surge of positive electricity, called a streamer, which can rise up through a building, a tree, or even a person.

When the two connect, an electrical current flows as negative charges fly down the channel towards earth and a visible flash of lightning streaks upward at some 200,000,000 mph (300,000,000 kph), transferring electricity as lightning in the process.

Some types of lightning, including the most common types, never leave the clouds but travel between differently charged areas within or between clouds. Other rare forms can be sparked by extreme forest fires, volcanic eruptions, and snowstorms. Ball lightning, a small, charged sphere that floats, glows, and bounces along oblivious to the laws of gravity or physics, still puzzles scientists.

About one to 20 cloud-to-ground lightning bolts is "positive lightning," a type that originates in the positively charged tops of stormclouds. These strikes reverse the charge flow of typical lightning bolts and are far stronger and more destructive. Positive lightning can stretch across the sky and strike "out of the blue" more than 10 miles from the storm cloud where it was born.

The Impact of a Lightning Strike

Lightning is not only spectacular, it's dangerous. About 2,000 people are killed worldwide by lightning each year. Hundreds more survive strikes but suffer from a variety of lasting symptoms, including memory loss, dizziness, weakness, numbness, and other life-altering ailments. Strikes can cause cardiac arrest and severe burns, but 9 of every 10 people survive. The average American has about a 1 in 5,000 chance of being struck by lightning during a lifetime.

Lightning's extreme heat will vaporize the water inside a tree, creating steam that may blow the tree apart. Cars are havens from lightning-but not for the reason that most believe. Tires conduct current, as do metal frames that carry a charge harmlessly to the ground.

Many houses are grounded by rods and other protection that conduct a lightning bolt's electricity harmlessly to the ground. Homes may also be inadvertently grounded by plumbing, gutters, or other materials. Grounded buildings offer protection, but occupants who touch running water or use a landline phone may be shocked by conducted electricity.

# data[].attributes.attachment_link.description
Lightning is an electrical discharge caused by imbalances between storm clouds and the ground, or within the clouds themselves. Most lightning occurs within the clouds. "Sheet lightning" describes a distant bolt that lights up an entire cloud base. Other visible bolts may appear as bead, ribbon, or rocket lightning.

# data[].attributes.body
Find out what causes lightning, fun facts about it and FAQs about lightning.

# data[].attributes.attachment_link.readable_text
Lightning

What is lightning?
Lightning is a bright flash of electricity produced by a thunderstorm. All thunderstorms produce lightning and are very dangerous. If you hear the sound of thunder, then you are in danger from lightning. Lightning kills and injures more people each year than hurricanes or tornadoes; between 75 to 100 people.

What causes lightning?
Lightning is an electric current. Within a thundercloud way up in the sky, many small bits of ice (frozen raindrops) bump into each other as they move around in the air. All of those collisions create an electric charge. After a while, the whole cloud fills up with electrical charges. The positive charges or protons form at the top of the cloud and the negative charges or electrons form at the bottom of the cloud. Since opposites attract, that causes a positive charge to build up on the ground beneath the cloud. The grounds electrical charge concentrates around anything that sticks up, such as mountains, people, or single trees. The charge coming up from these points eventually connects with a charge reaching down from the clouds and - zap - lightning strikes!

Have you ever rubbed your feet across carpet and then touched a metal door handle? If so, then you know that you can get shocked! Lightning works in the same way.

Click Here to see where lightning is currently striking across the U.S.
Lightning is approximately 54,000 degrees Fahrenheit. That is six times hotter than the surface of the sun!
How hot is lightning?

Lightning seems to be clear or a white-yellow color, but it really depends on the background.
What color is lightning?

Thunder is caused by lightning. When a lightning bolt travels from the cloud to the ground it actually opens up a little hole in the air, called a channel. Once then light is gone the air collapses back in and creates a sound wave that we hear as thunder. The reason we see lightning before we hear thunder is because light travels faster than sound!

What causes thunder?
If you see dark clouds, then lightning could be present, but the best thing you can do is to listen for thunder. If you hear thunder, then you need to go indoors or get in a car. Don't be outside, where lightning could strike! If your hair stands on end or your skin starts to tingle, lightning maybe about to strike. Get down on your hands and knees and keep your head tucked in. Do not lay flat, because it can give lightning a better chance of strike you.

How do you know if lightning is nearby?
Within those distant thunderstorms, the lightning bolts can be seen as much as 100 miles from us, depending on the height of the bolt, the clarity of the air, and our elevation. Thunder, in comparison, has a much shorter range of detection - usually less than 15 miles in a quiet rural setting and under 5 miles in a noisy city environment.

How far away can you see lightning and hear thunder?
All lightning is dangerous, but cloud-to-ground lightning is the most dangerous type of lightning. Most cloud-to-ground lightning strikes come from the negatively charged bottom of the cloud traveling to the positively charged ground below.

Why are you less likely to see static electricity in the summer?
In the summer, our dew points are much higher due to warm and humid air coming from the Gulf of Mexico and that is why we have humid weather. In the winter, our dew points are much lower due to cold and direr air coming from Canada. The lower the dew point the better it is to create static electricity, so that's why you see it more in the winter. Cloud-to-ground lightning bolts strike the tall objects, like trees and buildings. These lightning strikes can cause fire and property damage. If you're the tallest object, then lighting can strike you. Lightning is the second weather related killed.
What is cloud-to-ground lightning?

Intracloud lightning is the most common type of lightning. This occurs when there are both positive and negative charges within the same cloud. Usually, the process takes place within the cloud and looks like a bright flash of light which flickers.

Intercloud lightning is less common. It's when a lightning strike occurs when there are positive and negative charges within different clouds and the strike travels in the air between them.

What is intracloud lightning?
Forked lighting appears as jagged lines of light. They can have several branches. Forked lightning can be seen shooting from the clouds to the ground, from one cloud to another cloud, or from a cloud out into the air. This lightning can strike up to 10 miles away from a thunderstorm.

What is intercloud lightning?

Sheet lightning appears as flashes of light that seem to light up or illuminate entire clouds.

What is forked lightning?
Heat lightning is a term used to describe lightning flashes that are too far away from you to hear the thunder. The reason that it is called heat lightning is that it appears most often on a hot summer day when the sky is clear overhead.

High-altitude lightning has been given other names such as "red sprites," "green elves," and "blue jets." This form of lightning appears as brightly colored flashes, high above thunderstorms. You can't see these types of lightning from the ground. What is sheet lightning?

Ribbon lightning is when a bolt of lightning separates due to wind and appears as parallel lightning streaks.
What is heat lightning?

Chain or bead lightning is when a lightning bolt is broken into dotted lines while fading.

What is high-altitude lightning?
Ball lightning is a rare form of lightning. It usually appears as a reddish, luminous ball, but can come in any color. Ball lightning is usually spherical in shape and about one foot in diameter. Hissing noises originate from such balls and they sometimes make a loud noise when they explode.

What is ribbon lightning?

St. Elmo's Fire appears as a blue or greenish glow above pointed objects on the ground. It is created when tiny positively charged sparks reach up in response to negatively charges in the air or clouds above the ground. If a thunderstorm is nearby, St. Elmo's Fire might be seen right before a lightning strike.

What is chain or bead lightning?
Anvil lightning is a type of lightning referred to as "the bolt from the blue" because it often appears suddenly from a seemingly cloudless sky. A bolt at the top of a thunderstorm arcs away from the main cloud and strikes the ground where the skies above often appear clear.

What is ball lightning?
Yes, you can use thunder to tell how far away a storm is. Next time you see a storm, count the number of seconds between when you see the lightning and hear the thunder. Take the number of seconds and divide by 5 and that will tell you how far away the storm is in miles. For example: If you counted 10 seconds between the lightning and the thunder, the lightning is 2 miles away!

What is St. Elmo's Fire?

What is anvil lightning?

Can you tell how far away a storm is?

Know the Lingo

SEVERE THUNDERSTORM WATCH - A severe thunderstorm (damaging winds of 58 miles per hour or more, or 1" hail in diameter or greater) is likely to develop in your area.

PROTONS - They are particles with a positive charge. SEVERE THUNDERSTORM WARNING - A severe thunderstorm (damaging winds of 58 miles per hour or more, or hail three-fourths of an inch in diameter or greater) is taking place in your area.
ELECTRONS - They are particles with a negative charge.

STATIC ELECTRICITY - It is a form of electricity that is created when an object has too many electrons, giving it a negative charge.

LEADERS - A channel of charged air created by excess electrons in a thunderstorm cloud. A leader reaches from the cloud to the ground below, looking for positive charges.

RETURN STROKE - It's an electrical charge that travels from the ground to a thundercloud. This return stroke releases tremendous energy, bright light and thunder.

IF YOU'RE INDOORS: Avoid water. It's a great conductor of electricity, so do not take a shower, wash your hands, wash dishes or do laundry. Do not use a corded telephone. Lightning may strike exterior phone lines. Do not use electric equipment like computers and appliances during a storm. Stay away from windows and doors and stay off porches.
STREAMERS - A channel of charged air created by protons on the ground. They are created when leaders are created and reach from the ground to the sky looking for a leader to connect with.
IF SOMEONE IS STRUCK BY LIGHTNING: Call for help. Call 9-1-1 or send for help immediately. The injured person does not carry an electrical charge, so it is okay to touch them.

Know the Facts
A lightning flash is no more than one inch wide.

What we see as a flash of lightning may actually be four different strokes in exactly the same place, one right after another. That's why lightning appears to flicker.
Click Here to see if there are any active warnings in your area.

Lightning Safety Tips

IF YOU'RE OUTDOORS: Keep an eye at the sky. Look for darkening skies, flashes of lightning, or increasing winds. Lightning often proceeds rain, so don't wait for the rain to begin. If you hear the sound of thunder, go to a safe place immediately. The best place to go is a sturdy building or a car, but make sure the windows in the car are shut. Avoid sheds, picnic areas, baseball dugouts and bleachers. If there is no shelter around you, stay away from trees. Crouch down in the open area, keeping twice as far away from a tree as far as it is tall. Put your feet together and place your hands over your ears to minimize hearing damage from thunder. If you're with a group of people stay about 15 feet from each other. Stay out of water, because it's a great conductor of electricity. Swimming, wading, snorkeling and scuba diving are not safe. Also, don't stand in puddles and avoid metal. Stay away from clotheslines, fences, and drop your backpacks because they often have metal on them. If you're playing an outdoor activity, wait at least 30 minutes after the last observed lightning strike or thunder. Lightning Activities Lightning Experiment: Here is a great experiment that allows kids to make lightning in their mouth. It's a great way for them to understand how lightning works.Static Electricity Experiment: Here is an experiment that allows the kids to learn about static electricity by sticking a balloon to a wall. This teaches kids about the positive and negative charges and where they come from.

Static Electricity Experiment: Here is another static electricity experiment that bends water. This teaches kids about the positive and negative charges and where they come from.
Static Electricity Experiment: Here is yet another static electricity experiment with using a balloon and your hair. This teaches kids about the positive and negative charges and where they come from.
Thunder Experiment: This experiment allows kids to make thunder, in a way that allows them to understand how it is made by lightning.
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.

# data[].attributes.attachment_link.title
Weather Wiz Kids weather information for kids

# data[].attributes.attachment_link.description
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.

# data[].attributes.body
Simply, what is erosion

# data[].attributes.attachment_link.readable_text
Erosion is the process by which the surface of the Earth gets worn down. Erosion can be caused by natural elements such as wind and glacial ice. But anyone who has ever seen a picture of the Grand Canyon knows that nothing beats the slow steady movement of water when it comes to changing the Earth.

The key to erosion is something called "fluid flow." Water, air, and even ice are fluids because they tend to flow from one place to another due to the force of gravity. Of the three, liquid water is the most common agent of erosion because there's so much of it on the surface of the Earth.

To see what kind of effects water has on a model landscape, try my Science Lab.

# data[].attributes.attachment_link.description
Erosion is the process by which the surface of the Earth gets worn down. Erosion can be caused by natural elements such as wind and glacial ice. But anyone who has ever seen a picture of the Grand Canyon knows that nothing beats the slow steady movement of water when it comes to changing the Earth.

# data[].attributes.body
Learn what erosion is, how it caused and how humans are battling it.

# data[].attributes.attachment_link.readable_text
Erosion is the geological process in which earthen materials are worn away and transported by natural forces such as wind or water. A similar process, weathering, breaks down or dissolves rock, but does not involve movement. Erosion is the opposite of deposition, the geological process in which earthen materials are deposited, or built up, on a landform. Most erosion is performed by liquid water, wind, or ice (usually in the form of a glacier). If the wind is dusty, or water or glacial ice is muddy, erosion is taking place. The brown color indicates that bits of rock and soil are suspended in the fluid (air or water) and being transported from one place to another. This transported material is called sediment.

Physical erosion describes the process of rocks changing their physical properties without changing their basic chemical composition. Physical erosion often causes rocks to get smaller or smoother. Rocks eroded through physical erosion often form clastic sediments. Clastic sediments are composed of fragments of older rocks that have been transported from their place of origin. Landslides and other forms of mass wasting are associated with physical weathering. These processes cause rocks to dislodge from hillsides and crumble as they tumble down a slope.

Plant growth can also contribute to physical erosion in a process called bioerosion. Plants break up earthen materials as they take root, and can create cracks and crevices in rocks they encounter. Ice and liquid water can also contribute to physical erosion as their movement forces rocks to crash together or crack apart. Some rocks shatter and crumble, while others are worn away. River rocks are often much smoother than rocks found elsewhere, for instance, because they have been eroded by constant contact with other river rocks.

Erosion by Water

Liquid water is the major agent of erosion on Earth. Rain, rivers, floods, lakes, and the ocean carry away bits of soil and sand and slowly wash away the sediment. Rainfall produces four types of soil erosion: splash erosion, sheet erosion, rill erosion, and gully erosion.

Splash erosion describes the impact of a falling raindrop, which can scatter tiny soil particles as far as 0.6 meters (two feet).

Sheet erosion describes erosion caused by runoff.

Rill erosion describes erosion that takes place as runoff develops into discrete streams (rills).

Finally, gully erosion is the stage in which soil particles are transported through large channels.

The Fish River Canyon, in southern Namibia, is the largest canyon in Africa and a product of valley erosion. Over millions of years, the Fish River wore away at the hard gneiss bedrock, carving a canyon about 160 kilometers (99 miles) in length, 27 kilometers (17 miles) wide, and 550 meters (1,084 feet) deep.

The battering force of ocean waves also erodes seaside cliffs. The action of erosion can create an array of coastal landscape features. For example, erosion can bore holes that form caves. When water breaks through the back of the cave, it can create an arch. The continual pounding of waves can cause the top of the arch to fall, leaving nothing but rock columns called sea stacks. The seven remaining sea stacks of Twelve Apostles Marine National Park, in Victoria, Australia, are among the most dramatic and well-known of these features of coastal erosion.

Erosion by Wind

Erosion by Ice

Ice, usually in the form of glaciers, can erode the earth and create dramatic landforms. In frigid areas and on some mountaintops, glaciers move slowly downhill and across the land. As they move, they transport everything in their path, from tiny grains of sand to huge boulders. Rocks carried by glaciers scrape against the ground below, eroding both the ground and the rocks. In this way, glaciers grind up rocks and scrape away the soil. Moving glaciers gouge out basins and form steep-sided mountain valleys. Eroded sediment called moraine is often visible on and around glaciers.

Several times in Earth's history, vast glaciers covered parts of the Northern Hemisphere. These glacial periods are known as ice ages. Ice Age glaciers carved much of the modern northern North American and European landscape. Ice Age glaciers scoured the ground to form what are now the Finger Lakes in the U.S. state of New York, for example. They carved fjords, deep inlets along the coast of Scandinavia. The snout of a glacier eroded Cape Cod Bay, Massachusetts, U.S., and formed the recognizable fishhook shape of Cape Cod itself.

Today, in places such as Greenland and Antarctica, glaciers continue to erode the earth. Ice sheets there can be more than a mile thick, making it difficult for scientists to measure the speed and patterns of erosion. However, ice sheets do erode remarkably quickly-as much as half a centimeter (0.2 inch) every year.

Other Forces of Erosion

Factors Impacting Erosion

Some of the natural factors impacting erosion in a landscape include climate, topography, vegetation, and tectonic activity. Climate is perhaps the most influential force impacting the effect of erosion on a landscape. Climate includes precipitation and wind. Climate also includes seasonal variability, which influences the likelihood of weathered sediments being transported during a weather event such as a snowmelt, breeze, or hurricane. Topography, the shape of surface features of an area, can contribute to how erosion impacts that area. The earthen floodplains of river valleys are much more prone to erosion than rocky flood channels, which may take centuries to erode. Soft rock like chalk will erode more quickly than hard rocks like granite.

Vegetation can slow the impact of erosion. Plant roots adhere to soil and rock particles, preventing their transport during rainfall or wind events. Trees, shrubs, and other plants can even limit the impact of mass wasting events such as landslides and other natural hazards such as hurricanes. Deserts, which generally lack thick vegetation, are often the most eroded landscapes on the planet.

Finally, tectonic activity shapes the landscape itself, and thus influences the way erosion impacts an area. Tectonic uplift, for example, causes one part of the landscape to rise higher than others. In a span of about 5 million years, tectonic uplift caused the Colorado River to cut deeper and deeper into the Colorado Plateau, land in what is now the U.S. state of Arizona. It eventually formed the Grand Canyon, which is more than 1,600 meters (one mile) deep and as much as 29 kilometers (18 miles) wide in some places.

Erosion and People
Deposition, Soils, and Sediments
Eroded sediments have profoundly influenced the development of civilizations around the world. Agricultural development is often reliant on the nutrient-rich soils created by the accumulation of eroded earth. When the velocity of wind or water slows, eroded sediment is deposited in a new location. The sediment builds up in a process called sedimentation and creates fertile land. River deltas are made almost entirely of sediment that has eroded from the banks and bed of a river.

The rich delta soils of the San Joaquin and Sacramento rivers in northern California, for example, have created one of the most agriculturally productive areas in the world. Loess is an agriculturally rich sediment made almost entirely of wind-blown, eroded sediment.

The Yellow River in central China gets its name from the yellow loess blown into and suspended in its water. The fertile lands around the Yellow River have been among China's most productive for thousands of years.

Erosion is a natural process, but human activity can make it happen more quickly. Human activity altering the vegetation of an area is perhaps the biggest human factor contributing to erosion. Trees and plants hold soil in place. When people cut down forests or plow up grasses for agriculture and development, the soil is more vulnerable to washing or blowing away. Landslides become more common. Water rushes over exposed soil rather than soaking into it, causing flooding.

The rise in temperature is also quickly melting glaciers. The slower, more massive form of glacial erosion is being supplanted by the cumulative impact of rill, gully, and valley erosion. In areas downstream from glacial snouts, rapidly melting glaciers are contributing to sea level rise. The rising sea erodes beaches more quickly.

Erosion control is the process of reducing erosion by wind and water. Farmers and engineers must regularly practice erosion control. Sometimes, engineers simply install structures to physically prevent soil from being transported. Gabions are huge wireframes that hold boulders in place, for instance. Gabions are often placed near cliffs. These cliffs, often near the coast, have homes, businesses, and highways near them. When erosion by water or wind threatens to tumble the boulders toward buildings and cars, gabions protect landowners and drivers by holding the rocks in place.

Living shorelines are another form of erosion control in wetland areas. Living shorelines are constructed by placing native plants, stone, sand, and even living organisms such as oysters along wetland coasts. These plants help anchor the soil to the area, preventing erosion. By securing the land, living shorelines establish a natural habitat. They protect coastlines from powerful storm surges as well as erosion.

# data[].attributes.attachment_link.description
Erosion is the geological process in which earthen materials are worn away and transported by natural forces such as wind or water.

# data[].attributes.body
FAQs about tsunamis from the International Tsunami Information Center

# data[].attributes.attachment_link.title
Tsunami FAQs From the International Tsunami Information Center

# data[].attributes.attachment_link.description
In the deep ocean, tsunami wave amplitude is usually less than 1 m (3.3 feet). The crests of tsunami waves may be more than a hundred kilometers or more away from each other. Therefore, passengers on boats at sea, far away from shore where the water is deep, will not feel nor see the tsunami waves as they pass by underneath at high speeds.

# data[].attributes.body
National Geographic facts about Tornadoes.

# data[].attributes.attachment_link.readable_text
Tornadoes are vertical funnels of rapidly spinning air. Their winds may top 250 miles an hour and can clear a pathway a mile wide and 50 miles long.

Also known as twisters, tornadoes are born in thunderstorms and are often accompanied by hail. Giant, persistent thunderstorms called supercells spawn the most destructive tornadoes.

These violent storms occur around the world, but the United States is a major hotspot with about a thousand tornadoes every year.

" Tornado Alley," a region that includes the area in the eastern state of South Dakota, Nebraska, Kansas, Oklahoma, northern Texas, and eastern Colorado, is often home to the most powerful and destructive of these storms. U.S. tornadoes cause 80 deaths and more than 1,500 injuries per year.

What is a tornado?

A tornado is a violently rotating column of air that extends from a thunderstorm to the ground. It's often portended by a dark, greenish sky. Black storm clouds gather. Baseball-size hail may fall. A funnel suddenly appears, as though descending from a cloud. The funnel hits the ground and roars forward with a sound like that of a freight train approaching. The tornado tears up everything in its path.

Every U.S. state has experienced twisters, but Texas holds the record: an annual average of 120. Tornadoes have been reported in Great Britain, India, Argentina, and other countries, but they are most often seen in the United States.

Related to tornadoes, waterspouts are weak twisters that form over warm water. They sometimes move inland and become tornadoes.

Dust devils are small, rapidly rotating columns of air that are made visible by the dust and dirt they pick up. Dust devils are not associated with thunderstorms. Either are fire tornadoes, which can spawn from wildfires.

What causes tornadoes?

The most violent tornadoes come from supercells, large thunderstorms that have winds already in rotation. About one in a thousand storms becomes a supercell, and one in five or six supercells spawns off a tornado.

Tornadoes can occur at any time of year, but they are more common during a distinct season that begins in early spring for the states along the Gulf of Mexico. The season follows the jet stream -as it swings farther north, so does tornado activity. May generally has more tornadoes than any other month, but April's twisters are sometimes more violent. Farther north, tornadoes tend to be more common later in summer.

Although they can occur at any time of the day or night, most tornadoes form in the late afternoon. By this time the sun has heated the ground and the atmosphere enough to produce thunderstorms.

Tornadoes form when warm, humid air collides with cold, dry air.

The denser cold air is pushed over the warm air, usually producing thunderstorms. The warm air rises through the colder air, causing an updraft. The updraft will begin to rotate if winds vary sharply in speed or direction.

As the rotating updraft, called a mesocycle, draws in more warm air from the moving thunderstorm, its rotation speed increases. Cool air fed by the jet stream, a strong band of wind in the atmosphere, provides even more energy.

Water droplets from the mesocyclone's moist air form a funnel cloud. The funnel continues to grow and eventually it descends from the cloud. When it touches the ground, it becomes a tornado.

Characteristics of tornadoes

Twisters are usually accompanied or preceded by severe thunderstorms and high wlnds. Hail is also common.

Once a tornado hits the ground, it may live for as little as a few seconds or as long as three hours.

The average twister is about 660 feet wide and moves about 30 miles an hour. Most don't travel more than six miles before dying out.

Massive tornadoes, however-the ones capable of widespread destruction and many deaths-can roar along as fast as 300 miles an hour.

These measurements are scientists' best estimations. Anemometers, which measure wind speed, cannot withstand the enormous force of tornadoes to record them.

Using units F0 to F5, the Fujita scale measures a tornado's intensity by analyzing the damage the twister has done and then matching that to the wind speeds estimated to produce comparable damage. The United States now uses the EF (Enhanced Fujita) scale, which takes more variables into account when assigning wind speeds to a tornado.

Tornado destruction

Every year in the United States, tornadoes do about 400 million dollars in damage and kill about 70 people on average.

Extremely high winds tear homes and businesses apart. Winds can also destroy bridges, flip trains, send cars and trucks flying, tear the bark off trees, and suck all the water from a riverbed.

High winds sometimes kill or injure people by rolling them along the ground or dropping them from dangerous heights. But most tornado victims are struck by flying debris-roofing shingles, broken glass, doors, metal rods.

The number of average deaths per year in the United States used to be higher before improved forecasting and warning systems were put into place.

How tornadoes are forecasted

Meteorologists at the U.S. National Weather Service use Doppler radar, satellites, weather balloons, and computer modeling to watch the skies for severe storms and tornadic activity.

Doppler radars record wind speeds and identify areas of rotation within thunderstorms. Since Doppler radar has been in use, the warning time for tornadoes has grown from fewer than five minutes in the 1980s to an average of 13 minutes by the late 2000s.

When weather conditions are conducive for tornado formation, the National Weather Service issues a tornado watch. When a tornado has been sighted or indicated on radar, a tornado warning is issued.

Some scientists, meteorology buffs, and adrenaline junkies hit the road during tornado season to chase storms. Researchers race to place sensors in tornadoes' paths. The sensors measure data such as wind speed, barometric pressure, humidity, and temperature.

The challenge for researchers is being in the right place at the right time. Every morning they study weather conditions and head for the area that seems most likely to spawn a twister. They drive through severe storms, dodge lightning, face flash floods, and get pounded by hail-sometimes for years-before ever spotting a tornado.

All at considerable risk. In 2013, National Geographic Explorer Tim Samaras and his team were killed while trying to study a tornado in Oklahoma. ( See photos of Samaras's work.)

# data[].attributes.attachment_link.description
Learn how these deadly storms form and wreak havoc, and how you can reduce your risk.

# data[].attributes.body
Learn about what tsunamis are and what forces are involved.

# data[].attributes.attachment_link.description
On Dec. 26, 2004, a 9.0 magnitude earthquake-the largest earthquake in 40 years-occurred off the west coast of the Indonesian island of Sumatra. The earthquake triggered a tsunami in the Indian Ocean, the deadliest in world history. More than 226,000 died and twelve countries felt the devastation.

# data[].attributes.body
Learn about what tornadoes are and what forces are involved.

# data[].attributes.attachment_link.readable_text
Cite

Facts and figures about twisters

Although tornadoes can happen at any time of year, they are especially common during the spring and early summer. May and June are the peak months in terms of numbers of tornadoes, but April appears to be the deadliest month. Two of the all-time worst tornado disasters occurred in April. On April 3-4, 1974, 148 twisters struck 13 states, causing more than 300 deaths, and on April 27, 2011, 137 reported tornadoes swept through the south, killing nearly 300 people in six states. Most of the fatalities occurred in Alabama. May holds the record for experiencing the most tornadoes. In May 2003, there were 543 recorded tornadoes. On average, 60 people die each year as a result of tornadoes, mostly from flying and falling debris.

What Is a Tornado?

A tornado is a dark funnel-shaped cloud made up of violently rotating winds that can reach speeds of up to 300 m.p.h. The diameter of a tornado can vary between a few feet and a mile, and its track can extend from less than a mile to several hundred miles. Tornadoes generally travel in a northeast direction (depending on the prevailing winds) at speeds ranging from 20-60 m.p.h.

What Causes a Tornado?

Tornadoes are most often spawned by giant thunderstorms known as "supercells." These powerful, highly organized storms form when warm, moist air along the ground rushes upward, meeting cooler, drier air. As the rising warm air cools, the moisture it carries condenses, forming a massive thundercloud, sometimes growing to as much as 50,000 ft. in height. Variable winds at different levels of the atmosphere feed the updraft and cause the formation of the tornado's characteristic funnel shape.

Did you know?

April is the deadliest month for tornadoes [ more]

Where Do Tornadoes Occur?

The conditions that lead to the formation of tornadoes are most often met in the central and southern U.S., where warm, humid air from the Gulf of Mexico collides with cool, dry air from the Rockies and Canada. This area, dubbed "tornado alley," extends roughly from the Rocky Mountains to the Appalachians, and from Iowa and Nebraska to the Gulf of Mexico. Tornadoes can also occur elsewhere, though, including all U.S. states, Europe, Asia, and Australia.

What Kind of Destruction Do Tornadoes Cause?

The Fujita scale classifies tornadoes according to the damage they cause. Almost half of all tornadoes fall into the F1 or "moderate damage" category. These tornadoes reach speeds of 73-112 m.p.h. and can overturn automobiles and mobile homes, rip off the roofs of houses, and uproot trees. Only about 1 percent of tornadoes are classified as F5, causing "incredible damage." With wind speeds in excess of 261 m.p.h., these tornadoes are capable of lifting houses off their foundations and hurling them considerable distances.

Facts and figures about twisters

Although tornadoes can happen at any time of year, they are especially common during the spring and early summer. May and June are the peak months in terms of numbers of tornadoes, but April appears to be the deadliest month. Two of the all-time worst tornado disasters occurred in April. On April 3-4, 1974, 148 twisters struck 13 states, causing more than 300 deaths, and on April 27, 2011, 137 reported tornadoes swept through the south, killing nearly 300 people in six states. Most of the fatalities occurred in Alabama. May holds the record for experiencing the most tornadoes. In May 2003, there were 543 recorded tornadoes. On average, 60 people die each year as a result of tornadoes, mostly from flying and falling debris.

What Is a Tornado?

A tornado is a dark funnel-shaped cloud made up of violently rotating winds that can reach speeds of up to 300 m.p.h. The diameter of a tornado can vary between a few feet and a mile, and its track can extend from less than a mile to several hundred miles. Tornadoes generally travel in a northeast direction (depending on the prevailing winds) at speeds ranging from 20-60 m.p.h.

What Causes a Tornado?

Tornadoes are most often spawned by giant thunderstorms known as "supercells." These powerful, highly organized storms form when warm, moist air along the ground rushes upward, meeting cooler, drier air. As the rising warm air cools, the moisture it carries condenses, forming a massive thundercloud, sometimes growing to as much as 50,000 ft. in height. Variable winds at different levels of the atmosphere feed the updraft and cause the formation of the tornado's characteristic funnel shape.

Did you know?

April is the deadliest month for tornadoes [ more]

Where Do Tornadoes Occur?

The conditions that lead to the formation of tornadoes are most often met in the central and southern U.S., where warm, humid air from the Gulf of Mexico collides with cool, dry air from the Rockies and Canada. This area, dubbed "tornado alley," extends roughly from the Rocky Mountains to the Appalachians, and from Iowa and Nebraska to the Gulf of Mexico. Tornadoes can also occur elsewhere, though, including all U.S. states, Europe, Asia, and Australia.

What Kind of Destruction Do Tornadoes Cause?

The Fujita scale classifies tornadoes according to the damage they cause. Almost half of all tornadoes fall into the F1 or "moderate damage" category. These tornadoes reach speeds of 73-112 m.p.h. and can overturn automobiles and mobile homes, rip off the roofs of houses, and uproot trees. Only about 1 percent of tornadoes are classified as F5, causing "incredible damage." With wind speeds in excess of 261 m.p.h., these tornadoes are capable of lifting houses off their foundations and hurling them considerable distances.

# data[].attributes.attachment_link.description
Cite Although tornadoes can happen at any time of year, they are especially common during the spring and early summer. May and June are the peak months in terms of numbers of tornadoes, but April appears to be the deadliest month. Two of the all-time worst tornado disasters occurred in April.