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Tsunamis are just long waves - really long waves. But what is a wave? Sound waves, radio waves, even "the wave" in a stadium all have something in common with the waves that move across oceans. It takes an external force to start a wave, like dropping a rock into a pond or waves blowing across the sea.

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https://en.wikipedia.org/wiki/Tsunami

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The 2004 Indian Ocean tsunami at Ao Nang, Krabi Province, Thailand

3D tsunami animation

A tsunami ( (t)soo-NAH-mee, (t)suu-; from Japanese: 津波, 'harbour wave', pronounced ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater explosions (including detonations, landslides, glacier calvings, meteorite impacts and other disturbances) above or below water all have the potential to generate a tsunami. Unlike normal ocean waves, which are generated by wind, or tides, which are in turn generated by the gravitational pull of the Moon and the Sun, a tsunami is generated by the displacement of water from a large event.

Tsunami waves do not resemble normal undersea currents or sea waves because their wavelength is far longer. Rather than appearing as a breaking wave, a tsunami may instead initially resemble a rapidly rising tide. For this reason, it is often referred to as a tidal wave, although this usage is not favoured by the scientific community because it might give the false impression of a causal relationship between tides and tsunamis. Tsunamis generally consist of a series of waves, with periods ranging from minutes to hours, arriving in a so-called " wave train". Wave heights of tens of metres can be generated by large events. Although the impact of tsunamis is limited to coastal areas, their destructive power can be enormous, and they can affect entire ocean basins. The 2004 Indian Ocean tsunami was among the deadliest natural disasters in human history, with at least 230,000 people killed or missing in 14 countries bordering the Indian Ocean.

The Ancient Greek historian Thucydides suggested in his 5th century BC History of the Peloponnesian War that tsunamis were related to submarine earthquakes, but the understanding of tsunamis remained slim until the 20th century, and much remains unknown. Major areas of current research include determining why some large earthquakes do not generate tsunamis while other smaller ones do. This ongoing research is designed to help accurately forecast the passage of tsunamis across oceans as well as how tsunami waves interact with shorelines.

Terminology

The term "tsunami" is a borrowing from the Japanese tsunami , meaning "harbour wave." For the plural, one can either follow ordinary English practice and add an s, or use an invariable plural as in the Japanese. Some English speakers alter the word's initial to an by dropping the "t," since English does not natively permit /ts/ at the beginning of words, though the original Japanese pronunciation is /ts/. The term has become commonly accepted in English, although its literal Japanese meaning is not necessarily descriptive of the waves, which do not occur only in harbours.

Tsunami aftermath in Aceh, Indonesia, December 2004

Tsunamis are sometimes referred to as tidal waves. This once-popular term derives from the most common appearance of a tsunami, which is that of an extraordinarily high tidal bore. Tsunamis and tides both produce waves of water that move inland, but in the case of a tsunami, the inland movement of water may be much greater, giving the impression of an incredibly high and forceful tide. In recent years, the term "tidal wave" has fallen out of favour, especially in the scientific community, because the causes of tsunamis have nothing to do with those of tides, which are produced by the gravitational pull of the moon and sun rather than the displacement of water. Although the meanings of "tidal" include "resembling" or "having the form or character of" tides, use of the term tidal wave is discouraged by geologists and oceanographers.

A 1969 episode of the TV crime show Hawaii Five-O entitled "Forty Feet High and It Kills!" used the terms "tsunami" and "tidal wave" interchangeably.

Seismic sea wave

The term seismic sea wave is also used to refer to the phenomenon because the waves most often are generated by seismic activity such as earthquakes. Prior to the rise of the use of the term tsunami in English, scientists generally encouraged the use of the term seismic sea wave rather than tidal wave. However, like tidal wave, seismic sea wave is not a completely accurate term, as forces other than earthquakes-including underwater landslides, volcanic eruptions, underwater explosions, land or ice slumping into the ocean, meteorite impacts, and the weather when the atmospheric pressure changes very rapidly-can generate such waves by displacing water.

Other terms

The use of the term tsunami for waves created by landslides entering bodies of water has become internationally widespread in both scientific and popular literature, although such waves are distinct in origin from large waves generated by earthquakes. This distinction sometimes leads to the use of other terms for landslide-generated waves, including landslide-triggered tsunami, displacement wave, non-seismic wave, impact wave, and, simply, giant wave.

Lisbon earthquake and tsunami in November 1755

While Japan may have the longest recorded history of tsunamis,[citation needed ] the sheer destruction caused by the 2004 Indian Ocean earthquake and tsunami event mark it as the most devastating of its kind in modern times, killing around 230,000 people. The Sumatran region is also accustomed to tsunamis, with earthquakes of varying magnitudes regularly occurring off the coast of the island.

Tsunamis are an often underestimated hazard in the Mediterranean Sea and parts of Europe. Of historical and current (with regard to risk assumptions) importance are the 1755 Lisbon earthquake and tsunami (which was caused by the Azores-Gibraltar Transform Fault), the 1783 Calabrian earthquakes, each causing several tens of thousands of deaths and the 1908 Messina earthquake and tsunami. The tsunami claimed more than 123,000 lives in Sicily and Calabria and is among the most deadly natural disasters in modern Europe. The Storegga Slide in the Norwegian Sea and some examples of tsunamis affecting the British Isles refer to landslide and meteotsunamis predominantly and less to earthquake-induced waves.

As early as 426 BC the Greek historian Thucydides inquired in his book History of the Peloponnesian War about the causes of tsunami, and was the first to argue that ocean earthquakes must be the cause. The oldest human record of a tsunami dates back to 479 BC, in the Greek colony of Potidaea, thought to be triggered by an earthquake. The tsunami may have saved the colony from an invasion by the Achaemenid Empire.

The cause, in my opinion, of this phenomenon must be sought in the earthquake. At the point where its shock has been the most violent the sea is driven back, and suddenly recoiling with redoubled force, causes the inundation. Without an earthquake I do not see how such an accident could happen.

The Roman historian Ammianus Marcellinus ( Res Gestae 26.10.15-19) described the typical sequence of a tsunami, including an incipient earthquake, the sudden retreat of the sea and a following gigantic wave, after the 365 AD tsunami devastated Alexandria.

The principal generation mechanism of a tsunami is the displacement of a substantial volume of water or perturbation of the sea. This displacement of water is usually caused by earthquakes, but can also be attributed to landslides, volcanic eruptions, glacier calvings or more rarely by meteorites and nuclear tests. However, the possibility of a meteorite causing a tsunami is debated.

Seismicity

Tsunamis can be generated when the sea floor abruptly deforms and vertically displaces the overlying water. Tectonic earthquakes are a particular kind of earthquake that are associated with the Earth's crustal deformation; when these earthquakes occur beneath the sea, the water above the deformed area is displaced from its equilibrium position. More specifically, a tsunami can be generated when thrust faults associated with convergent or destructive plate boundaries move abruptly, resulting in water displacement, owing to the vertical component of movement involved. Movement on normal (extensional) faults can also cause displacement of the seabed, but only the largest of such events (typically related to flexure in the outer trench swell) cause enough displacement to give rise to a significant tsunami, such as the 1977 Sumba and 1933 Sanriku events.

Over-riding plate bulges under strain, causing tectonic uplift.

Plate slips, causing subsidence and releasing energy into water.

The energy released produces tsunami waves.

Tsunamis have a small wave height offshore, and a very long wavelength (often hundreds of kilometres long, whereas normal ocean waves have a wavelength of only 30 or 40 metres), which is why they generally pass unnoticed at sea, forming only a slight swell usually about 300 millimetres (12 in) above the normal sea surface. They grow in height when they reach shallower water, in a wave shoaling process described below. A tsunami can occur in any tidal state and even at low tide can still inundate coastal areas.

On April 1, 1946, the 8.6 M w  Aleutian Islands earthquake occurred with a maximum Mercalli intensity of VI ( Strong). It generated a tsunami which inundated Hilo on the island of Hawaii with a 14-metre high (46 ft) surge. Between 165 and 173 were killed. The area where the earthquake occurred is where the Pacific Ocean floor is subducting (or being pushed downwards) under Alaska.

Examples of tsunamis originating at locations away from convergent boundaries include Storegga about 8,000 years ago, Grand Banks in 1929, and Papua New Guinea in 1998 (Tappin, 2001). The Grand Banks and Papua New Guinea tsunamis came from earthquakes which destabilised sediments, causing them to flow into the ocean and generate a tsunami. They dissipated before travelling transoceanic distances.

The cause of the Storegga sediment failure is unknown. Possibilities include an overloading of the sediments, an earthquake or a release of gas hydrates (methane etc.).

The 1960 Valdivia earthquake ( 9.5), 1964 Alaska earthquake ( M w 9.2), 2004 Indian Ocean earthquake ( M w 9.2), and 2011 Tōhoku earthquake ( M w9.0) are recent examples of powerful megathrust earthquakes that generated tsunamis (known as teletsunamis) that can cross entire oceans. Smaller ( M w 4.2) earthquakes in Japan can trigger tsunamis (called local and regional tsunamis) that can devastate stretches of coastline, but can do so in only a few minutes at a time.

Landslides

The Tauredunum event was a large tsunami on Lake Geneva in 563 CE, caused by sedimentary deposits destabilized by a landslide.

In the 1950s, it was discovered that tsunamis larger than had previously been believed possible can be caused by giant submarine landslides. These large volumes of rapidly displaced water transfer energy at a faster rate than the water can absorb. Their existence was confirmed in 1958, when a giant landslide in Lituya Bay, Alaska, caused the highest wave ever recorded, which had a height of 524 metres (1,719 ft). The wave did not travel far as it struck land almost immediately. The wave struck three boats-each with two people aboard-anchored in the bay. One boat rode out the wave, but the wave sank the other two, killing both people aboard one of them.

Another landslide-tsunami event occurred in 1963 when a massive landslide from Monte Toc entered the reservoir behind the Vajont Dam in Italy. The resulting wave surged over the 262-metre (860 ft)-high dam by 250 metres (820 ft) and destroyed several towns. Around 2,000 people died. Scientists named these waves megatsunamis.

Some geologists claim that large landslides from volcanic islands, e.g. Cumbre Vieja on La Palma ( Cumbre Vieja tsunami hazard) in the Canary Islands, may be able to generate megatsunamis that can cross oceans, but this is disputed by many others.

In general, landslides generate displacements mainly in the shallower parts of the coastline, and there is conjecture about the nature of large landslides that enter the water. This has been shown to subsequently affect water in enclosed bays and lakes, but a landslide large enough to cause a transoceanic tsunami has not occurred within recorded history. Susceptible locations are believed to be the Big Island of Hawaii, Fogo in the Cape Verde Islands, La Reunion in the Indian Ocean, and Cumbre Vieja on the island of La Palma in the Canary Islands; along with other volcanic ocean islands. This is because large masses of relatively unconsolidated volcanic material occurs on the flanks and in some cases detachment planes are believed to be developing. However, there is growing controversy about how dangerous these slopes actually are.

Volcanic eruptions

Other than by landslides or sector collapse, volcanoes may be able to generate waves by pyroclastic flow submergence, caldera collapse, or underwater explosions. Tsunamis have been triggered by a number of volcanic eruptions, including the 1883 eruption of Krakatoa, and the 2022 Hunga Tonga-Hunga Ha'apai eruption. Over 20% of all fatalities caused by volcanism during the past 250 years are estimated to have been caused by volcanogenic tsunamis.

Debate has persisted over the origins and source mechanisms of these types of tsunamis, such as those generated by Krakatoa in 1883, and they remain lesser understood than their seismic relatives. This poses a large problem of awareness and preparedness, as exemplified by the eruption and collapse of Anak Krakatoa in 2018, which killed 426 and injured thousands when no warning was available.

It is still regarded that lateral landslides and ocean-entering pyroclastic currents are most likely to generate the largest and most hazardous waves from volcanism; however, field investigation of the Tongan event, as well as developments in numerical modelling methods, currently aim to expand the understanding of the other source mechanisms.

Meteorological

Some meteorological conditions, especially rapid changes in barometric pressure, as seen with the passing of a front, can displace bodies of water enough to cause trains of waves with wavelengths. These are comparable to seismic tsunamis, but usually with lower energies. Essentially, they are dynamically equivalent to seismic tsunamis, the only differences being 1) that meteotsunamis lack the transoceanic reach of significant seismic tsunamis, and 2) that the force that displaces the water is sustained over some length of time such that meteotsunamis cannot be modelled as having been caused instantaneously. In spite of their lower energies, on shorelines where they can be amplified by resonance, they are sometimes powerful enough to cause localised damage and potential for loss of life. They have been documented in many places, including the Great Lakes, the Aegean Sea, the English Channel, and the Balearic Islands, where they are common enough to have a local name, rissaga. In Sicily they are called marubbio and in Nagasaki Bay, they are called abiki. Some examples of destructive meteotsunamis include 31 March 1979 at Nagasaki and 15 June 2006 at Menorca, the latter causing damage in the tens of millions of euros.

Meteotsunamis should not be confused with storm surges, which are local increases in sea level associated with the low barometric pressure of passing tropical cyclones, nor should they be confused with setup, the temporary local raising of sea level caused by strong on-shore winds. Storm surges and setup are also dangerous causes of coastal flooding in severe weather but their dynamics are completely unrelated to tsunami waves. They are unable to propagate beyond their sources, as waves do.

Human-made or triggered tsunamis

The accidental Halifax Explosion in 1917 triggered a 18-meter high tsunami in the harbour.

There have been studies of the potential of the induction of and at least one actual attempt to create tsunami waves as a tectonic weapon.

In World War II, the New Zealand Military Forces initiated Project Seal, which attempted to create small tsunamis with explosives in the area of today's Shakespear Regional Park; the attempt failed.

There has been considerable speculation on the possibility of using nuclear weapons to cause tsunamis near an enemy coastline. Even during World War II consideration of the idea using conventional explosives was explored. Nuclear testing in the Pacific Proving Ground by the United States seemed to generate poor results. Operation Crossroads fired two 20 kilotonnes of TNT (84 TJ) bombs, one in the air and one underwater, above and below the shallow (50 m (160 ft)) waters of the Bikini Atoll lagoon. Fired about 6 km (3.7 mi) from the nearest island, the waves there were no higher than 3-4 m (9.8-13.1 ft) upon reaching the shoreline. Other underwater tests, mainly Hardtack I/Wahoo (deep water) and Hardtack I/Umbrella (shallow water) confirmed the results. Analysis of the effects of shallow and deep underwater explosions indicate that the energy of the explosions does not easily generate the kind of deep, all-ocean waveforms which are tsunamis; most of the energy creates steam, causes vertical fountains above the water, and creates compressional waveforms. Tsunamis are hallmarked by permanent large vertical displacements of very large volumes of water which do not occur in explosions.

Characteristics

When the wave enters shallow water, it slows down and its amplitude (height) increases.

The wave further slows and amplifies as it hits land. Only the largest waves crest.

Tsunamis are caused by earthquakes, landslides, volcanic explosions, glacier calvings, and bolides. They cause damage by two mechanisms: the smashing force of a wall of water travelling at high speed, and the destructive power of a large volume of water draining off the land and carrying a large amount of debris with it, even with waves that do not appear to be large.

While everyday wind waves have a wavelength (from crest to crest) of about 100 metres (330 ft) and a height of roughly 2 metres (6.6 ft), a tsunami in the deep ocean has a much larger wavelength of up to 200 kilometres (120 mi). Such a wave travels at well over 800 kilometres per hour (500 mph), but owing to the enormous wavelength the wave oscillation at any given point takes 20 or 30 minutes to complete a cycle and has an amplitude of only about 1 metre (3.3 ft). This makes tsunamis difficult to detect over deep water, where ships are unable to feel their passage.

The velocity of a tsunami can be calculated by obtaining the square root of the depth of the water in metres multiplied by the acceleration due to gravity (approximated to 10 m/s ²). For example, if the Pacific Ocean is considered to have a depth of 5000 metres, the velocity of a tsunami would be = ≈ 224 metres per second (730 ft/s), which equates to a speed of about 806 kilometres per hour (501 mph). This is the formula used for calculating the velocity of shallow-water waves. Even the deep ocean is shallow in this sense because a tsunami wave is so long (horizontally from crest to crest) by comparison.

The reason for the Japanese name "harbour wave" is that sometimes a village's fishermen would sail out, and encounter no unusual waves while out at sea fishing, and come back to land to find their village devastated by a huge wave.

As the tsunami approaches the coast and the waters become shallow, wave shoaling compresses the wave and its speed decreases below 80 kilometres per hour (50 mph). Its wavelength diminishes to less than 20 kilometres (12 mi) and its amplitude grows enormously-in accord with Green's law. Since the wave still has the same very long period, the tsunami may take minutes to reach full height. Except for the very largest tsunamis, the approaching wave does not break, but rather appears like a fast-moving tidal bore. Open bays and coastlines adjacent to very deep water may shape the tsunami further into a step-like wave with a steep-breaking front.

When the tsunami's wave peak reaches the shore, the resulting temporary rise in sea level is termed run up. Run up is measured in metres above a reference sea level. A large tsunami may feature multiple waves arriving over a period of hours, with significant time between the wave crests. The first wave to reach the shore may not have the highest run-up.

About 80% of tsunamis occur in the Pacific Ocean, but they are possible wherever there are large bodies of water, including lakes. However, tsunami interactions with shorelines and the seafloor topography are extremely complex, which leaves some countries more vulnerable than others. For example, the Pacific coasts of the United States and Mexico lie adjacent to each other, but the United States has recorded ten tsunamis in the region since 1788, while Mexico has recorded twenty-five since 1732. Similarly, Japan has had more than a hundred tsunamis in recorded history, while the neighboring island of Taiwan has registered only two, in 1781 and 1867.

An illustration of the rhythmic "drawback" of surface water associated with a wave. It follows that a very large drawback may herald the arrival of a very large wave.

All waves have a positive and negative peak; that is, a ridge and a trough. In the case of a propagating wave like a tsunami, either may be the first to arrive. If the first part to arrive at the shore is the ridge, a massive breaking wave or sudden flooding will be the first effect noticed on land. However, if the first part to arrive is a trough, a drawback will occur as the shoreline recedes dramatically, exposing normally submerged areas. The drawback can exceed hundreds of metres, and people unaware of the danger sometimes remain near the shore to satisfy their curiosity or to collect fish from the exposed seabed.

A typical wave period for a damaging tsunami is about twelve minutes. Thus, the sea recedes in the drawback phase, with areas well below sea level exposed after three minutes. For the next six minutes, the wave trough builds into a ridge which may flood the coast, and destruction ensues. During the next six minutes, the wave changes from a ridge to a trough, and the flood waters recede in a second drawback. Victims and debris may be swept into the ocean. The process repeats with succeeding waves.

Scales of intensity and magnitude

As with earthquakes, several attempts have been made to set up scales of tsunami intensity or magnitude to allow comparison between different events.

Intensity scales

The first scales used routinely to measure the intensity of tsunamis were the Sieberg-Ambraseys scale (1962), used in the Mediterranean Sea and the Imamura-Iida intensity scale (1963), used in the Pacific Ocean. The latter scale was modified by Soloviev (1972), who calculated the tsunami intensity " I" according to the formula:

where is the "tsunami height" in meters, averaged along the nearest coastline, with the tsunami height defined as the rise of the water level above the normal tidal level at the time of occurrence of the tsunami.[62] This scale, known as the Soloviev-Imamura tsunami intensity scale, is used in the global tsunami catalogues compiled by the NGDC/NOAA[63] and the Novosibirsk Tsunami Laboratory as the main parameter for the size of the tsunami.

This formula yields:

I = 2 for = 2.8 metres

I = 3 for = 5.5 metres

I = 4 for = 11 metres

I = 5 for = 22.5 metres

etc.

In 2013, following the intensively studied tsunamis in 2004 and 2011, a new 12-point scale was proposed, the Integrated Tsunami Intensity Scale (ITIS-2012), intended to match as closely as possible to the modified ESI2007 and EMS earthquake intensity scales.

Magnitude scales

The first scale that genuinely calculated a magnitude for a tsunami, rather than an intensity at a particular location was the ML scale proposed by Murty & Loomis based on the potential energy.[61] Difficulties in calculating the potential energy of the tsunami mean that this scale is rarely used. Abe introduced the tsunami magnitude scale , calculated from,

where h is the maximum tsunami-wave amplitude (in m) measured by a tide gauge at a distance R from the epicentre, a, b and D are constants used to make the M t scale match as closely as possible with the moment magnitude scale.

Tsunami heights

Diagram showing several measures to describe a tsunami size, including height, inundation and run-up

Several terms are used to describe the different characteristics of tsunami in terms of their height:

Amplitude, Wave Height, or Tsunami Height: Refers to the height of a tsunami relative to the normal sea level at the time of the tsunami, which may be tidal High Water, or Low Water. It is different from the crest-to-trough height which is commonly used to measure other type of wave height.

Run-up Height, or Inundation Height: The height reached by a tsunami on the ground above sea level, Maximum run-up height refers to the maximum height reached by water above sea level, which is sometimes reported as the maximum height reached by a tsunami.

Flow Depth: Refers to the height of tsunami above ground, regardless of the height of the location or sea level.

(Maximum) Water Level: Maximum height above sea level as seen from trace or water mark. Different from maximum run-up height in the sense that they are not necessarily water marks at inundation line/limit.

Warnings and predictions

Calculated travel time map for the 1964 Alaska tsunami (in hours)

Drawbacks can serve as a brief warning. People who observe drawback (many survivors report an accompanying sucking sound) can survive only if they immediately run for high ground or seek the upper floors of nearby buildings.

In 2004, ten-year-old Tilly Smith of Surrey, England, was on Maikhao beach in Phuket, Thailand with her parents and sister, and having learned about tsunamis recently in school, told her family that a tsunami might be imminent. Her parents warned others minutes before the wave arrived, saving dozens of lives. She credited her geography teacher, Andrew Kearney.

In the 2004 Indian Ocean tsunami drawback was not reported on the African coast or any other east-facing coasts that it reached. This was because the initial wave moved downwards on the eastern side of the megathrust and upwards on the western side. The western pulse hit coastal Africa and other western areas.

A tsunami cannot be precisely predicted, even if the magnitude and location of an earthquake is known. Geologists, oceanographers, and seismologists analyse each earthquake and based on many factors may or may not issue a tsunami warning. However, there are some warning signs of an impending tsunami, and automated systems can provide warnings immediately after an earthquake in time to save lives. One of the most successful systems uses bottom pressure sensors, attached to buoys, which constantly monitor the pressure of the overlying water column.

Regions with a high tsunami risk typically use tsunami warning systems to warn the population before the wave reaches land. On the west coast of the United States, which is prone to tsunamis from the Pacific Ocean, warning signs indicate evacuation routes. In Japan, the populace is well-educated about earthquakes and tsunamis, and along Japanese shorelines, tsunami warning signs remind people of the natural hazards along with a network of warning sirens, typically at the top of the cliffs of surrounding hills.

The Pacific Tsunami Warning System is based in Honolulu, Hawaiʻi. It monitors Pacific Ocean seismic activity. A sufficiently large earthquake magnitude and other information triggers a tsunami warning. While the subduction zones around the Pacific are seismically active, not all earthquakes generate a tsunami. Computers assist in analysing the tsunami risk of every earthquake that occurs in the Pacific Ocean and the adjoining land masses.

As a direct result of the Indian Ocean tsunami, a re-appraisal of the tsunami threat for all coastal areas is being undertaken by national governments and the United Nations Disaster Mitigation Committee. A tsunami warning system is being installed in the Indian Ocean.

One of the deep water buoys used in the DART tsunami warning system

Computer models can predict tsunami arrival, usually within minutes of the arrival time. Bottom pressure sensors can relay information in real time. Based on these pressure readings and other seismic information and the seafloor's shape ( bathymetry) and coastal topography, the models estimate the amplitude and surge height of the approaching tsunami. All Pacific Rim countries collaborate in the Tsunami Warning System and most regularly practise evacuation and other procedures. In Japan, such preparation is mandatory for government, local authorities, emergency services and the population.

Along the United States west coast, in addition to sirens, warnings are sent on television and radio via the National Weather Service, using the Emergency Alert System.

Possible animal reaction

Some zoologists hypothesise that some animal species have an ability to sense subsonic Rayleigh waves from an earthquake or a tsunami. If correct, monitoring their behaviour could provide advance warning of earthquakes and tsunamis. However, the evidence is controversial and is not widely accepted. There are unsubstantiated claims about the Lisbon quake that some animals escaped to higher ground, while many other animals in the same areas drowned. The phenomenon was also noted by media sources in Sri Lanka in the 2004 Indian Ocean earthquake. It is possible that certain animals (e.g., elephants) may have heard the sounds of the tsunami as it approached the coast. The elephants' reaction was to move away from the approaching noise. By contrast, some humans went to the shore to investigate and many drowned as a result.

Mitigation

A seawall at Tsu, Mie Prefecture in Japan

In some tsunami-prone countries, earthquake engineering measures have been taken to reduce the damage caused onshore.

Japan, where tsunami science and response measures first began following a disaster in 1896, has produced ever-more elaborate countermeasures and response plans. The country has built many tsunami walls of up to 12 metres (39 ft) high to protect populated coastal areas. Other localities have built floodgates of up to 15.5 metres (51 ft) high and channels to redirect the water from an incoming tsunami. However, their effectiveness has been questioned, as tsunamis often overtop the barriers.

The Fukushima Daiichi nuclear disaster was directly triggered by the 2011 Tōhoku earthquake and tsunami, when waves exceeded the height of the plant's sea wall. Iwate Prefecture, which is an area at high risk from tsunami, had tsunami barriers walls ( Taro sea wall) totalling 25 kilometres (16 mi) long at coastal towns. The 2011 tsunami toppled more than 50% of the walls and caused catastrophic damage.

The Okushiri, Hokkaidō tsunami, which struck within two to five minutes of the earthquake on July 12, 1993, created waves 30 metres (100 ft) tall-as high as a 10-storey building. The port town of Aonae was completely surrounded by a tsunami wall, but the waves washed right over the wall and destroyed all the wood-framed structures in the area. The wall may have succeeded in slowing down and moderating the height of the tsunami, but it did not prevent major destruction and loss of life.

References

IOC Tsunami Glossary by the Intergovernmental Oceanographic Commission (IOC) at the International Tsunami Information Centre (ITIC) of UNESCO

Tsunami Terminology at NOAA

In June 2011, the VOA Special English service of the Voice of America broadcast a 15-minute program on tsunamis as part of its weekly Science in the News series. The program included an interview with an NOAA official who oversees the agency's tsunami warning system. A transcript and MP3 of the program, intended for English learners, can be found at The Ever-Present Threat of Tsunamis.

abelard.org. tsunamis: tsunamis travel fast but not at infinite speed. retrieved March 29, 2005.

Dudley, Walter C. & Lee, Min (1988: 1st edition) Tsunami! ISBN 0-8248-1125-9 website

Iwan, W.D., editor, 2006, Summary report of the Great Sumatra Earthquakes and Indian Ocean tsunamis of December 26, 2004 and March 28, 2005: Earthquake Engineering Research Institute, EERI Publication #2006-06, 11 chapters, 100-page summary, plus CD-ROM with complete text and supplementary photographs, EERI Report 2006-06. ISBN 1-932884-19-X website

Kenneally, Christine (December 30, 2004). "Surviving the Tsunami." Slate. website

Lambourne, Helen (March 27, 2005). "Tsunami: Anatomy of a disaster." . website

Macey, Richard (January 1, 2005). "The Big Bang that Triggered A Tragedy," The Sydney Morning Herald, p 11-quoting Dr Mark Leonard, seismologist at Geoscience Australia.

Interactive Map of Historical Tsunamis from NOAA National Centers for Environmental Information

Tappin, D; 2001. Local tsunamis. Geoscientist. 11-8, 4-7.

Girl, 10, used geography lesson to save lives, Telegraph.co.uk

Philippines warned to prepare for Japan's tsunami, Noypi.ph

Further reading

Boris Levin, Mikhail Nosov: Physics of tsunamis. Springer, Dordrecht 2009, ISBN 978-1-4020-8855-1.

Kontar, Y. A. et al.: Tsunami Events and Lessons Learned: Environmental and Societal Significance. Springer, 2014. ISBN 978-94-007-7268-7 (print); ISBN 978-94-007-7269-4 (eBook)

Kristy F. Tiampo: Earthquakes: simulations, sources and tsunamis. Birkhäuser, Basel 2008, ISBN 978-3-7643-8756-3.

Linda Maria Koldau: Tsunamis. Entstehung, Geschichte, Prävention, (Tsunami development, history and prevention) C.H. Beck, Munich 2013 (C.H. Beck Reihe Wissen 2770), ISBN 978-3-406-64656-0 (in German).

Walter C. Dudley, Min Lee: Tsunami! University of Hawaii Press, 1988, 1998, Tsunami! University of Hawai'i Press 1999, ISBN 0-8248-1125-9, ISBN 978-0-8248-1969-9.

Charles L. Mader: Numerical Modeling of Water Waves CRC Press, 2004, ISBN 0-8493-2311-8.

External links

# data[].attributes.attachment_link.description
A tsunami ( (t)soo-NAH-mee, (t)suu- ; from Japanese: 津波, 'harbour wave', pronounced ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake.

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A tsunami is a series of ocean waves that sends surges of water, sometimes reaching heights of over 100 feet (30.5 meters), onto land. These walls of water can cause widespread destruction when they crash ashore.

What Causes a Tsunami?

These awe-inspiring waves are typically caused by large, undersea earthquakes at tectonic plate boundaries. When the ocean floor at a plate boundary rises or falls suddenly, it displaces the water above it and launches the rolling waves that will become a tsunami.

Most tsunamis-about 80 percent-happen within the Pacific Ocean's "Ring of Fire," a geologically active area where tectonic shifts make volcanoes and earthquakes common.

Tsunamis may also be caused by underwater landslides or volcanic eruptions. They may even be launched, as they frequently were in Earth's ancient past, by the impact of a large meteorite plunging into an ocean.

Tsunamis race across the sea at up to 500 miles (805 kilometers) an hour-about as fast as a jet airplane. At that pace, they can cross the entire expanse of the Pacific Ocean in less than a day. And their long wavelengths mean they lose very little energy along the way.

In deep ocean, tsunami waves may appear only a foot or so high. But as they approach shoreline and enter shallower water they slow down and begin to grow in energy and height. The tops of the waves move faster than their bottoms do, which causes them to rise precipitously.

What Happens When It Hits Land

A tsunami's trough, the low point beneath the wave's crest, often reaches shore first. When it does, it produces a vacuum effect that sucks coastal water seaward and exposes harbor and sea floors. This retreating of sea water is an important warning sign of a tsunami, because the wave's crest and its enormous volume of water typically hit shore five minutes or so later. Recognizing this phenomenon can save lives.

A tsunami is usually composed of a series of waves, called a wave train, so its destructive force may be compounded as successive waves reach shore. People experiencing a tsunami should remember that the danger may not have passed with the first wave and should await official word that it is safe to return to vulnerable locations.

Some tsunamis do not appear on shore as massive breaking waves but instead resemble a quickly surging tide that inundates coastal areas.

The best defense against any tsunami is early warning that allows people to seek higher ground. The Pacific Tsunami Warning System, a coalition of 26 nations headquartered in Hawaii, maintains a web of seismic equipment and water level gauges to identify tsunamis at sea. Similar systems are proposed to protect coastal areas worldwide.

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Learn more about these destructive surges of water from National Geographic.

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https://www.cdc.gov/disasters/tsunamis/index.html

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centers for disease control and prevention

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Tsunamis, also known as seismic sea waves, are a series of enormous waves created by an underwater disturbance such as an earthquake, landslide, volcanic eruption, or meteorite. A tsunami can strike anywhere along most of the U.S. coastline. Learn more about tsunamis and get information about health concerns after a tsunami including food and water safety.

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Learn about and see pictures of auroras, snow rollers, rogue waves, ball lightning, and other freaky forces of nature!

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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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Tornado Facts For Kids

Enjoy our fun tornado facts for kids! Learn what tornadoes are, how fast they spin, how far they can travel, where most tornadoes occur, the difference between an F0 tornado and an F5 tornado, what a waterspout is and much more.

Read on to check out our wide range of information on twisters.

A tornado is a rapidly spinning tube of air that touches both the ground and a cloud above.

Tornadoes are sometimes called twisters.

Not all tornadoes are visible but their high wind speeds and rapid rotation often form a visible funnel of condensed water.

The Fujita Scale is a common way of measuring the strength of tornadoes. The scale ranges from F0 tornadoes that cause minimal damage through to F5 tornadoes which cause massive damage.

Most tornadoes have wind speeds less than 100 miles per hour (161 kilometres per hour).

Extreme tornadoes can reach wind speeds of over 300 miles per hour (483 kilometres per hour).

Most tornadoes travel a few miles before exhausting themselves.

Extreme tornadoes can travel much further, sometimes over 100 miles (161kilometres).

The Tri-State Tornado that travelled through parts of Missouri, Illinois and Indiana in 1925 left a path of destruction over 219 miles (352 kilometres) long.

The Tri-State Tornado was the deadliest tornado in US history, killing 695 people.

The USA averages around 1200 tornadoes every year, more than any other country.

The majority of these tornadoes occur in a geographically unique area nicknamed 'Tornado Alley'.

US States most often hit by tornadoes include Texas, Kansas, Oklahoma and Florida.

In 1989 the deadliest tornado ever recorded in the world killed around 1300 people in Bangladesh.

In the southern hemisphere tornadoes usually rotate in a clockwise direction.

In the northern hemisphere tornadoes usually rotate in a counterclockwise direction.

A tornado that occurs over water is often called a waterspout.

Weather radars are used to detect tornadoes and give advanced warning.

Basements and other underground areas are the safest places to seek refuge during a tornado. It is also a good idea to stay away from windows.

Make a tornado in a bottle or watch some amazing tornado video footage.

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Fun Tornado Facts for Kids - Interesting Information about Twisters

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Tornado Facts For Kids Enjoy our fun tornado facts for kids! Learn what tornadoes are, how fast they spin, how far they can travel, where most tornadoes occur, the difference between an F0 tornado and an F5 tornado, what a waterspout is and much more.

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What is a Tornado? | Weather Science | SciShow Kids

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Find out what causes these deadly twisters—and how to stay safe.

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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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At least one tornado touched down in central Kansas on Wednesday as severe weather swept through the area.

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TORNADO SAFETY

In an average year, 1000 tornadoes are reported, resulting in 80 deaths and over 1,500 injuries. Tornadoes have been reported in every state and can happen at any time of the year. Take tornadoes seriously, because with winds blowing at 200 mph or more, they can destroy just about anything in its path. Always listen to the radio and television for the latest information and instructions for your area.

A TORNADO WATCH means tornadoes are possible in your area. Stay tuned to the radio or television news.

A TORNADO WARNING means a tornado is either on the ground or has been detected by Doppler radar. Seek shelter immediately!

BEFORE A TORNADO:

Have a disaster plan. Make sure everyone knows where to go in case a tornado threatens.

Make sure you know which county or parish you live in.

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 TORNADO:

Go to a basement.

If you do not have a basement, go to an interior room without windows on the lowest floor such as a bathroom or closet.

If you can, get under a sturdy piece of furniture, like a table.

If you live in a mobile home get out. They offer little protection against tornadoes.

Get out of automobiles. Do not try to outrun a tornado in your car, leave it immediately.

If you're outside, go to a ditch or low lying area and lie flat in it.

Stay away from fallen power lines and stay out of damaged areas.

IF YOU'RE AT SCHOOL DURING A TORNADO:

Every school should have a disaster plan and have frequent drills.

Basements offer the best protection.

Schools without basements should use interior rooms and hallways on the lowest floor away from windows.

Crouch down on your knees and protect your head with your arms.

AFTER A TORNADO:

Stay indoors until it is safe to come out.

Check for injured or trapped people, without putting yourself in danger.

Watch out for downed power lines.

Use a flashlight to inspect your home.

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

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Insane Violent Tornado Destroys EVERYTHING!!

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Insane Violent Tornado Destroys EVERYTHING!!

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DRY SKIES: CHECK OUT PINECONES

Pinecones are one way to tell if dry weather is coming. Pinecones open their scales when the weather gets extremely dry. They do this to scatter their seeds. When the air is moist, they close up to keep their seeds dry. Pine seeds are transported by the wind, so they have to stay as dry and as light as possible in order to fly. Dust and sand, of course, travel in much the same way. So if a pinecone's scales are open, be on the lookout for dry weather.

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You don't need a weather app to predict rain or shine-you just need nature!

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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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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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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 flood is an overflow of water on normally dry ground. This is most commonly due to an overflowing river, a dam break, snowmelt, or heavy rainfall. Less commonly happening are tsunamis, storm surge.

The most deadly flooding was in 1931 in China and killed between 2,000,000 and 4,000,000 people. The Kerala flood in India was another flood that has destroyed people's houses.

During a flood, people try to move themselves and their most precious belongings to higher ground quickly. The process of leaving homes in search of a safe place is called flood evacuation.

Bangladesh is the most flood prone area in the world.

Pollution of drinking water

During a flood there is plenty of water logging and overflow of water, but it is mostly polluted and not safe to drink. If people drink this dirty water, they may suffer from diseases such as typhoid and cholera, hepatitis and other such diseases. People can get ready to survive a flood by filling many containers with fresh and clean drinking water and storing other emergency supplies; like: medicine and food. During flood people try to go to higher sides because the flood water wouldn't reach high areas. Also drains overflow and mix with clean water and people who drink it might fall ill.

Floods can happen on flat or low-lying areas when water is supplied by rainfall or snowmelt more rapidly than it can either infiltrate or run off. The excess accumulates in place, sometimes to hazardous depths. Surface soil can become saturated, which effectively stops infiltration, where the water table is shallow, such as a floodplain, or from intense rain from one or a series of storms. Infiltration also is slow to negligible through frozen ground, rock, concrete, paving, or roofs. Areal flooding begins in flat areas like floodplains and in local depressions not connected to a stream channel, because the velocity of overland flow depends on the surface slope. Endorheic basins may experience areal flooding during periods when precipitation exceeds evaporation.

Riverine (Channel)

Floods occur in all types of river and stream channels, from the smallest ephemeral streams in humid zones to normally-dry channels in arid climates to the world's largest rivers. When overland flow occurs on tilled fields, it can result in a muddy flood where sediments are picked up by run off and carried as suspended matter or bed load. Localized flooding may be caused or exacerbated by drainage obstructions such as landslides, ice, debris, or beaver dams.

Slow-rising floods most commonly occur in large rivers with large catchment areas. The increase in flow may be the result of sustained rainfall, rapid snow melt, monsoons, or tropical cyclones. However, large rivers may have rapid flooding events in areas with dry climate, since they may have large basins but small river channels and rainfall can be very intense in smaller areas of those basins.

Rapid flooding events, including flash floods, more often occur on smaller rivers, rivers with steep valleys, rivers that flow for much of their length over impermeable terrain, or normally-dry channels. The cause may be localized convective precipitation (intense thunderstorms) or sudden release from an upstream impoundment created behind a dam, landslide, or glacier.

Flash floods are the most common flood type in normally-dry channels in arid zones, known as arroyos in the southwest United States and many other names elsewhere. In that setting, the first flood water to arrive is depleted as it wets the sandy stream bed. The leading edge of the flood thus advances more slowly than later and higher flows. As a result, the rising limb of the hydrograph becomes ever quicker as the flood moves downstream, until the flow rate is so great that the depletion by wetting soil becomes insignificant.

Estuarine and coastal

Flooding in estuaries is commonly caused by a combination of storm surges caused by winds and low barometric pressure and large waves meeting high upstream river flows.

Coastal areas may be flooded by storm surges combining with high tides and large wave events at sea, resulting in waves over-topping flood defenses or in severe cases by tsunami or tropical cyclones. A storm surge, from either a tropical cyclone or an extratropical cyclone, falls within this category. Research from the NHC (National Hurricane Center) explains: "Storm surge is an additional rise of water generated by a storm, over and above the predicted astronomical tides. Storm surge should not be confused with storm tide, which is defined as the water level rise due to the combination of storm surge and the astronomical tide. This rise in water level can cause extreme flooding in coastal areas particularly when storm surge coincides with spring tide, resulting in storm tides reaching up to 20 feet or more in some cases."

Urban flooding

Catastrophic

Catastrophic riverine flooding is usually associated with major infrastructure failures such as the collapse of a dam, but they may also be caused by drainage channel modification from a landslide, earthquake or volcanic eruption. Examples include outburst floods and lahars. Tsunamis can cause catastrophic coastal flooding, most commonly resulting from undersea earthquakes.

Causes of floods

Flooding is usually caused when a volume of water within a water body, such as a lake, overflows outside it. Sometimes if a dam breaks, it suddenly releases a large amount of water. The result is that some of the water travels to land, and 'floods' the area. Many rivers are in a channel, between river banks. They flood when the strength of the river causes it to flow beyond the banks. This is more common at bends or meanders.

Flood damage can be prevented by moving away from places that flood. However, people have long liked to have their homes and businesses alongside water because water is good for agriculture and transport and in other ways. Floods are also caused due to improper management of drains.

Rainfall is the most common cause. Snow melt is also a cause of flooding. Tsunamis and Storm Surge are less common ways that floods happen. Coastal Flooding is another common cause of flooding, and this is caused by low pressure systems or storms.

Flood safety planning

In the United States, the National Weather Service gives out the advice "Turn Around, Don't Drown" for floods; that is, it recommends that people get out of the area of a flood, rather than trying to cross it. At the most basic level, the best defense against floods is to seek higher ground for high-value uses while balancing the foreseeable risks with the benefits of occupying flood hazard zones. Critical community-safety facilities, such as hospitals, emergency-operations centers, and police, fire, and rescue services, should be built in areas least at risk of flooding. Structures, such as bridges, that must unavoidably be in flood hazard areas should be designed to withstand flooding. Areas most at risk for flooding could be put to valuable uses that could be abandoned temporarily as people retreat to safer areas when a flood is imminent.

Planning for flood safety involves many aspects of analysis and engineering, including:

observation of previous and present flood heights and inundated areas,

statistical, hydrologic, and hydraulic model analyses,

mapping inundated areas and flood heights for future flood scenarios,

long-term land use planning and regulation,

engineering design and construction of structures to control or withstand flooding,

intermediate-term monitoring, forecasting, and emergency-response planning, and

short-term monitoring, warning, and response operations.

Each topic presents distinct yet related questions with varying scope and scale in time, space, and the people involved. Attempts to understand and manage the mechanisms at work in floodplains have been made for at least six millennia.

In the United States, the Association of State Floodplain Managers works to promote education, policies, and activities that mitigate current and future losses, costs, and human suffering caused by flooding and to protect the natural and beneficial functions of floodplains - all without causing adverse impacts. A portfolio of best practice examples for disaster mitigation in the United States is available from the Federal Emergency Management Agency.

In many countries around the world, waterways prone to floods are often carefully managed. Defenses such as detention basins, levees, bunds, reservoirs, and weirs are used to prevent waterways from overflowing their banks. When these defenses fail, emergency measures such as sandbags or portable inflatable tubes are often used to try to stem flooding. Coastal flooding has been addressed in portions of Europe and the Americas with coastal defenses, such as sea walls, beach nourishment, and barrier islands.

In the riparian zone near rivers and streams, erosion control measures can be taken to try to slow down or reverse the natural forces that cause many waterways to meander over long periods of time. Flood controls, such as dams, can be built and maintained over time to try to reduce the occurrence and severity of floods as well. In the United States, the U.S. Army Corps of Engineers maintains a network of such flood control dams.

In areas prone to urban flooding, one solution is the repair and expansion of man-made sewer systems and stormwater infrastructure. Another strategy is to reduce impervious surfaces in streets, parking lots and buildings through natural drainage channels, porous paving, and wetlands (collectively known as green infrastructure or sustainable urban drainage systems (SUDS)). Areas identified as flood-prone can be converted into parks and playgrounds that can tolerate occasional flooding. Ordinances can be adopted to require developers to retain stormwater on site and require buildings to be elevated, protected by floodwalls and levees, or designed to withstand temporary inundation. Property owners can also invest in solutions themselves, such as re-landscaping their property to take the flow of water away from their building and installing rain barrels, sump pumps, and check valves.

In some areas, the presence of certain species (such as beavers) can be beneficial for flood control reasons. Beavers build and maintain beaver dams which will reduce the height of flood waves moving down the river (during periods of heavy rains), and will reduce or eliminate damage to human structures, at the cost of minor flooding near the dams (often on farmland). Besides this, they also boost wildlife populations and filter pollutants (manure, fertilisers, slurry). UK environment minister Rebecca Pow stated that in the future the beavers could be considered a "public good" and landowners would be paid to have them on their land.

Related pages

Images for kids

A dog sitting on top of 2 feet of mud deposited by flooding in the 2018 Kerala floods in India. Flooding not only creates water damage, but can also deposit large amounts of sediment.

Minor flooding in a parking lot off Juniper street Atlanta on Christmas Eve from thunderstorms caused by an El Nino event. The same El Nino caused recorded highs for January in Atlanta

Flash flooding caused by heavy rain falling in a short amount of time.

Dozens of villages were inundated when rain pushed the rivers of northwestern Bangladesh over their banks in early October 2005. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured the top image of the flooded Ghaghat and Atrai Rivers on October 12, 2005. The deep blue of the rivers is spread across the countryside in the flood image.

In Spanish: Inundación para niños

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Floods may:

Find safe shelter right away.

Do not walk, swim or drive through flood waters. Turn Around, Don't Drown!

Remember, just six inches of moving water can knock you down, and one foot of moving water can sweep your vehicle away.

Stay off bridges over fast-moving water.

Depending on the type of flooding:

Evacuate if told to do so.

Move to higher ground or a higher floor.

Stay where you are.

Preparing for a Flood
Make a plan for your household, including your pets, so that you and your family know what to do, where to go, and what you will need to protect yourselves from flooding. Learn and practice evacuation routes, shelter plans, and flash flood response. Gather supplies, including non-perishable foods, cleaning supplies, and water for several days, in case you must leave immediately or if services are cut off in your area.

In Case of Emergency
Keep important documents in a waterproof container. Create password-protected digital copies. Protect your property. Move valuables to higher levels. Declutter drains and gutters. Install check valves. Consider a sump pump with a battery.

Evacuate immediately, if told to evacuate. Never drive around barricades. Local responders use them to safely direct traffic out of flooded areas.

Contact your healthcare provider If you are sick and need medical attention. Wait for further care instructions and shelter in place, if possible. If you are experiencing a medical emergency, call 9-1-1.

Listen to EAS, NOAA Weather Radio or local alerting systems for current emergency information and instructions regarding flooding.

Do not walk, swim or drive through flood waters. Turn Around. Don't Drown!

Stay off bridges over fast-moving water. Fast-moving water can wash bridges away without warning.

Stay inside your car if it is trapped in rapidly moving water. Get on the roof if water is rising inside the car.

Get to the highest level if trapped in a building. Only get on the roof if necessary and once there signal for help. Do not climb into a closed attic to avoid getting trapped by rising floodwater.

Pay attention to authorities for information and instructions. Return home only when authorities say it is safe.

Avoid driving except in emergencies.

Wear heavy work gloves, protective clothing and boots during clean up and use appropriate face coverings or masks if cleaning mold or other debris.

People with asthma and other lung conditions and/or immune suppression should not enter buildings with indoor water leaks or mold growth that can be seen or smelled. Children should not take part in disaster cleanup work.

Be aware that snakes and other animals may be in your house.

Be aware of the risk of electrocution. Do not touch electrical equipment if it is wet or if you are standing in water. Turn off the electricity to prevent electric shock if it is safe to do so.

Avoid wading in floodwater, which can be contaminated and contain dangerous debris. Underground or downed power lines can also electrically charge the water.

Use a generator or other gasoline-powered machinery ONLY outdoors and away from windows.

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Floods are the most common natural disaster in the United States. Learn how to stay safe when a flood threatens. Prepare for a flood During a flood After a flood Associated content Flooding is a temporary overflow of water onto land that is normally dry. Floods are the most common disaster in the United States.

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Rain is good but to much of it isn't it can cause floods and floods can cause cars to float and alot of traffic

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

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

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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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Drought Stretches Across American West | NBC Nightly News

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How California's Droughts Lead to Other Disasters

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

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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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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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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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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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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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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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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 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 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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There is a ritual of sorts that goes on in Florida every year when folks get wind of the news that a big storm is a-brewing. Windows are boarded, boats are dry-docked and grocery stores and home improvement stores are picked clean of anything that might come in handy in the unlikely event that a massive hurricane hits.

What keeps people going through the annual routine of following spaghetti models and prepping for the big one in the Sunshine State and other coastal areas is that many have seen a hurricane or two, and they know the kind of serious destruction these storms can cause. From an 18th-century hurricane that ravaged the Caribbean to the devastating blow issued by Sandy in 2012, history is replete with stories of the wreckage and ruin that come with a major storm.

By definition, a hurricane is a tropical storm with winds above 74 miles per hour (119 kilometers per hour). The systems occur all over the world. In the Western Atlantic and Eastern Pacific Oceans, they are called hurricanes. In the Indian Ocean and South Pacific, they are called cyclones and in the Western Pacific, they are called typhoons.

The following hurricanes aren't necessarily the deadliest of all time, or the costliest. But they all sit at the intersection of property damage, powerful winds and human tragedy, and all captured the world's attention for differing reasons. We've listed them in order of lives lost.

Hurricane Michael decimated the Florida Panhandle, particularly in the Panama City Beach, Mexico Beach and Cape San Blas, when it made landfall Oct. 10, 2018 as a Category 5. It was the strongest hurricane ever to hit that area and only the second Category 5 to make landfall on the Gulf Coast. Michael also was the first Category 5 storm to hit the U.S. since Hurricane Andrew in 1992.

Hurricane Michael started as a typical weak October Caribbean tropical system. However, once the system moved over warm Gulf of Mexico waters, it rapidly intensified and became a major hurricane with sustained winds of 161 miles per hour (259 kilometers per hour). The catastrophic damage was caused from wind and storm surge, and spread inland into southwest Georgia.

Michael caused 16 deaths in four states, including Florida, Virginia, North Carolina and Georgia. Damage estimates from the Insurance Information Institute from Michael total between $9 and $12 billion.

After traveling through the Gulf of Mexico in late August 2017, Hurricane Harvey arrived in the United States as a Category 4 storm. At the time it was the first major hurricane to make landfall in the continental United States in a decade, after 2005's Hurricane Wilma. The arrival of Harvey coincided with its peak intensity: winds of 130 miles per hour (215 kilometers per hour). Coastal communities in Texas like Corpus Christi and Galveston were hard-hit, but the most striking damage was in Houston, the fourth-largest city in the country.

Flooding in Houston was severe, as Harvey remained over the area for days, dumping up to 50 inches (127 centimeters) of water in certain locations. That's the same amount of rainfall Houston usually sees in an entire year, all deposited in a four-day span, and the area's ecosystem and manmade environment were both overwhelmed. The storm also affected communities like Beaumont, Texas, where the entire city was cut off from fresh drinking water. Then-FEMA director Brock Long called Harvey " probably the worst disaster the state's seen."

More than 13,000 people required rescuing throughout Texas, and an overall 30,000 people from that state were displaced by floodwaters. And while Texas was hardest-hit, the storm also affected communities in Louisiana, Alabama, Tennessee and beyond. Damage estimates were around $121 billion, making it the fourth-most expensive hurricane in U.S. history.

Harvey claimed at least 82 lives in Texas. Officials say that number includes those who died as a direct result of the storm, drowning in flash floods or on roads.

When Hurricane Camille hit in August 1969, it was a nasty storm that brought heavy flooding and 200-mile per hour (320-kilometer per hour) winds to the Gulf Coast and later Virginia. It also was one of only two Category 5 hurricanes to hit the Continental U.S. since 1900. (Since then two others have made landfall: Andrew in 1992 and Michael in 2018.) After forming near the Cayman Islands in August 1969, Camille first blew through Cuba as a Category 3 but intensified in the Gulf of Mexico making a beeline for Mississippi where it made landfall between Bay St. Louis and Pass Christian Aug. 18. Exact wind speed at landfall is unknown, as weather instruments were destroyed, though estimates put suggest gusts were as high as 200 miles per hour (322 kilometers per hour). However, with 900 mb pressure at landfall, Camille still ranks as the second most intense hurricane to hit the continental U.S.

Winds as high as 100 miles per hour were clocked across much of Southern Mississippi, leading to wind damage far inland. A 24-foot (7-meter) storm surge also contributed to major devastation in Mississippi. Camille eventually weakened to a tropical storm as it moved up the East Coast and reached Virginia, but the storm continued to dump upward of 20 inches (51 centimeters) of rain on the region, contributing to flash flooding and mudslides just 120 miles (193 kilometers) from the nation's capital. The storm resulted in 256 deaths and more than $1.4 billion in damage.

Camille played an important role in hurricane tracking in that it spawned the creation of the Saffir-Simpson Hurricane Wind Scale, which ranks storms from categories 1 to 5 based on wind speed. Category 1 hurricanes blow winds ranging from 74 to 95 miles (119 to 153 kilometers), while those in the Category 5 range feature wind speeds of more than 156 miles (251 kilometers) an hour. The system is designed to give residents in danger zones a better idea of what to expect from a brewing storm.

Hurricane Katrina is often referred to as a man-made, rather than natural, disaster by those who fault infrastructure problems for the decimation caused by this storm that ravaged New Orleans and other parts of the Gulf Coast.

On Aug. 26, 2005, Hurricane Katrina looked like a hurricane that was fizzling out, but it began rapidly strengthening to Category 5 levels over warm water in the Gulf of Mexico. By Aug. 28, a mandatory evacuation order was issued for New Orleans. As the Category 3 hurricane reached the city, water topped over its systems of levees causing them to break and the streets to flood. Eventually, 80 percent of New Orleans was underwater.

Katrina left residents who couldn't - or chose not to - evacuate stranded in their homes with waters rising around them. Forty percent of hurricane-related deaths were from drowning. Slow federal government reaction to the plight of those affected led to claims of incompetence and even deliberate disregard for poor and Black people.

In all, Hurricane Katrina claimed 1,833 lives and at $161 billion is considered the costliest hurricane in U.S. history. The Federal Emergency Management Agency called it "the single most catastrophic natural disaster in U.S. history."

Hurricane Katrina also displaced 400,000 people to areas like Houston and Atlanta. Many never returned. An upgraded system of levees was completed in 2013, but officials are worried about the massive cost of maintaining them with a shrunken tax base.

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The Americas have been hit with some major hurricanes throughout the decades. But which were the worst ones in history?

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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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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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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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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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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

Learn more about hurricanes, typhoons, and cyclones at National Geographic.

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Learn what causes these deadly storms-and how to stay safe.

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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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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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Wherever there is a shortage of rain over a long period of time, there is drought. Drought affects plants, animals, and people. It is a serious problem for farmers and for the people who depend on the crops they produce.

Drought may occur almost anywhere in the world. Deserts receive very little rain all year. They are sometimes said to be in a permanent drought. Places that have a rainy season and a dry season have seasonal drought during the dry season. Other places can experience drought at any time.

Drought results from changes in Earth's atmosphere. Some droughts are caused by shifts in the winds that normally bring rain to an area. Others are caused by changing ocean currents, which affect the temperature and moisture of the air.

Severe droughts can last for months or years. When this happens no crops will grow. As a result many people and animals may die of famine, or lack of food. Severe droughts often force people and animals to move to find water. Some farmers go to places where they think conditions will be better for their crops and animals. Some people give up farming altogether. They move to cities to find other types of work.

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Wherever there is a shortage of rain over a long period of time, there is drought. Drought affects plants, animals, and people. It is a serious problem for farmers and for...

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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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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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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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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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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.

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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.