Natural disaster

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A natural disaster is a catastrophe that occurs when a hazardous physical event (such as a volcanic eruption, earthquake, landslide, hurricane, or any of the other natural phenomena listed below) precipitates extensive damage to property, a large number of casualties, or both. In areas where there are no human interests, natural phenomena do not result in natural disasters.

A disaster is a social disruption that can occur at the level of the individual, the community, or the state (Kreps 1986).

The extent of casualties and damage to property resulting from a natural disaster depends on the capacity of the population to resist the disaster (Bankoff et al. 2004). This understanding is crystallized in the formulation: "disasters occur when hazards meet vulnerability" (Blaikie, 1994).

In 2000, the United Nations launched the International Strategy for Disaster Reduction (ISDR) to address the underlying causes of vulnerability and to build disaster-resilient communities by promoting increased awareness of the importance of disaster reduction as an integral component of sustainable development, with the goal of reducing human, social, economic and environmental losses due to hazards of all kinds (UN/ISDR, 2000).


Common natural phenomena that can result in natural disasters

Blizzards and snowstorms

Main article: Blizzard
Main article: Winter storm

A snowstorm is a winter storm in which the primary form of precipitation is snow. When such a storm is accompanied by winds above 32 mph that severely reduce visibility, it becomes a blizzard. Hazards from snowstorms and blizzards include traffic-related accidents, hypothermia for those unable to find shelter, as well as major disruptions to transportation and fuel and power distribution systems.


Main article: Drought

A drought is a long-lasting weather pattern consisting of dry conditions with very little or no precipitation. During this period, food and water supplies can run low, and other conditions, such as famine, can result. Droughts can last for several years and are particularly damaging in areas in which the residents depend on agriculture for survival. The Dust Bowl is a famous example of a severe drought.


Main article: Earthquake

An earthquake is a sudden shift or movement in the tectonic plate in the Earth's crust. On the surface, this is manifested by a moving and shaking of the ground, and can be massively damaging to poorly built structures. The most powerful earthquakes can destroy even the best built of structures. In addition, they can trigger secondary disasters, such as tsunamis and volcanic eruptions. Earthquakes occur along fault lines, and are unpredictable. They are capable of killing hundreds of thousands of people, such as in the 1976 Tangshan and 2004 Indian Ocean earthquakes.


Main article: Epidemic

An epidemic is a massive outbreak and spread of an infectious disease, and is historically the most dangerous of all natural disasters. Different epidemics are caused by different diseases, and different epidemics have included the Black Death, smallpox, and AIDS. The Spanish flu of 1918 was the deadliest ever epidemic, having been responsible for the deaths of 25-40 million people. The Black Death, which occurred in the 14th Century, killed over 20 million people, one third of Europe's population.


Main article: Famine

Famine is a natural disaster characterized by a widespread lack of food in a region, and can be characterized as a lack of agriculture foodstuffs, a lack of livestock, or a general lack of all foodstuffs required for basic nutrition and survival. Famine is almost always caused by pre-existing conditions, such as drought, but its effects may be exacerbated by social factors, such as war. Particularly devastating examples include the Ethiopian famine and the Irish Potato Famine.


Main article: Flood

A flood is a natural disaster caused by too much rain or water in a location, and could be caused by many different sets of conditions. Floods can be caused by prolonged rainfall from a storm, including thunderstorms, rapid melting of large amounts of snow, or rivers which swell from excess precipitation upstream and cause widespread damage to areas downstream, or less frequently the bursting of man-made dams or levees. A river which floods particularly often is the Huang He in China, and a particularly damaging flood was the Great Flood of 1931.

Forest fire

Main article: Forest fire

A forest fire is a natural disaster consisting of a fire which destroys a forested area, and can be a great danger to people who live in forests as well as wildlife. Forest fires are generally started by lightning, but also by human negligence or arson, and can burn thousands of square kilometers. An example of a severe forest fire is the Oakland Hills firestorm.


Main article: Hailstorm

A hailstorm is a natural disaster where a thunderstorm produces numerous hailstones which damage the location in which they fall. Hailstorms can be especially devastating to farm fields, ruining crops and damaging equipment. A particularly damaging hailstorm hit Munich, Germany on August 31, 1986, felling thousands of trees and causing millions of dollars in insurance claims.

Heat wave

Main article: Heat wave

A heat wave is a disaster characterized by heat which is considered extreme and unusual in the area in which it occurs. Heat waves are rare and require specific combinations of weather events to take place, and may include temperature inversions, katabatic winds, or other phenomena. The worst heat wave in recent history was the European Heat Wave of 2003.


Main article: Hurricane
Main article: Cyclones
Main article: Typhoons

A hurricane is a cyclonic storm system which forms over the oceans. It is caused by evaporated water which comes off of the ocean and becomes a storm. The Coriolis Effect causes the storms to spin, and a hurricane is declared when this spinning mass of storms attains a wind speed greater than 74mph. In different parts of the world hurricanes are known as cyclones or typhoons. The former occur in the Indian Ocean, while the latter occur in the Eastern Pacific Ocean. The deadliest hurricane ever was the 1970 Bhola cyclone; the deadliest Atlantic hurricane was the Great_Hurricane_of_1780, which devastated Martinique, St. Eustatius and Barbados.

Ice storm

Main article: Ice storm

An ice storm is a particular weather event in which precipitation falls as rain, due to atmosphere conditions, but in an area in which the temperature is below the freezing point of water. The rain falls to the ground, and immediately turns to ice, accumulating in that fashion. A heavy ice storm can cause large accumulations of ice cause trees to fall over or lose branches, and power lines to snap. The worst recent ice storm was the 1998 Ice Storm that struck eastern Canada and areas of the US northeast.


Main article: Lahar

A Lahar is a type of natural disaster closely related to a volcanic eruption, and involves a large amount of material, including mud, rock, and ash sliding down the side of the volcano at a rapid pace. These flows can destroy entire towns in seconds and kill thousands of people. The Tangiwai disaster is an excellent example, as is the one which killed an estimated 23,000 people in Armero, Colombia, during the 1985 eruption of Nevado del Ruiz.

Landslides and mudslides

Main article: Landslide

A landslide is a disaster closely related to an avalanche, but instead of occurring with snow, it occurs involving actual elements of the ground, including rocks, trees, parts of houses, and anything else which may happen to be swept up. Landslides can be caused by earthquakes, volcanic eruptions, or general instability in the surrounding land. Mudslides, or mud flows, are a special case of landslides, in which heavy rainfall causes loose soil on steep terrain to collapse and slide downwards (see also Lahar); these occur with some regularity in parts of California after periods of heavy rain.


Main article: Sinkhole

A localized depression in the surface topography, usually caused by the collapse of a subterranean structure, such as a cave. Although rare, large sinkholes that develop suddenly in populated areas can lead to the collapse of buildings and other structures.


Main article: Tornado

A tornado is a natural disaster resulting from a thunderstorm. Tornadoes are violent, rotating columns of air which can blow at speeds between 50 and 300 mph, and possibly higher. Tornadoes can occur one at a time, or can occur in large tornado outbreaks along squall lines or in other large areas of thunderstorm development. The most violent tornado ever recorded in terms of wind speed was the tornado which swept through Moore, Oklahoma on May 3, 1999. This tornado has wind speeds of 318mph measured by mobile doppler radar devices.


Main article: Tsunami

A tsunami is a giant wave of water which rolls into the shore of an area with a height of over 15 m (50 ft). It comes from Japanese words "津波" meaning harbor and wave. Tsunami can be caused by undersea earthquakes as in the 2004 Indian Ocean Earthquake, or by landslides such as the one which occurred at Lituya Bay, Alaska. The tsunami generated by the 2004 Indian Ocean Earthquake currently ranks as the deadliest tsunami in recorded history. The highest Tsunami ever recorded was estimated to be 85m (278 ft.) high. It appeared on April 24th, off Ishigaki Island, Japan.

Volcanic eruption

Main article: Volcano

This natural disaster is caused by the eruption of a volcano, and eruptions come in many forms. They range from daily small eruptions which occur in places like Kilauea, in Hawaii, or extremely infrequent supervolcano eruptions in places like Lake Toba. The greatest volcanic explosion occurred when Krakatoa in Indonesia blew up in 1883, hurling rocks 55km (34 miles) in the air. The explosion was heard as far away as Australia and generated a 40m. (131 ft.) high tsunami; 36,000 people died. The greatest volcanic eruption was that of Mt. Tambora on Sumbawa, Indonesia in 1815, which threw up more than 100 cubic km. (24cu. miles) of ash. The island was lowered by 1250m (4100 ft.); 92,000 people were killed.

Extreme natural disasters

Ice age

Main article: Ice age

An ice age is a geologic period, but could also be viewed in the light of a catastrophic natural disaster, since in an ice age, the climate all over the world would change and places which were once considered habitable would then be too cold to permanently inhabit. A side effect of an ice age could possibly be a famine, caused by a worldwide drought.

Impact event

Main article: Impact event

An impact event is a natural disaster in which an extraterrestrial piece of rock or other material collides with the Earth. The exact consequences of a direct Earth impact would vary greatly with size of the colliding object, although in cases of medium to large impacts short-term climate change and a general failure of agriculture. An example would be the Tunguska event.

Solar flare

Main article: Solar flare

A solar flare is a phenomenon where the sun suddenly releases a great amount of solar radiation, much more than normal. It is theorized that these releases of radiation could cause a widespread failure of communications technology across the globe. The exact implications of such a failure are unknown. Further studies are being carried out.


Main article: Supervolcano

A supervolcano is a eruption which is thousands of times more massive than a normal eruption. If a volcano expels at least 1000 cubic kilometers of material, it is delcared a supervolcano. The last eruption of this magnitude occurred over 75,000 years ago at Lake Toba. If such an eruption were to occur today, a wholesale general die-off of both animals and humans would occur, as well as crapping your pants


Main article: Megatsunami

Megatsunami is a term used by the popular media to describe very large tsunamis. They are a highly local effect, either occurring on shores extremely close to the origin of a tsunami, or in deep, narrow inlets. The largest waves are caused by a very large landslide, such as a collapsing island, into a body of water. They can potentially reach 20 km inland in low-lying regions.

See also


  • Abbott, Peter Leon. Natural Disasters, McGraw-Hill Science/Engineering/Math, 3 edition (2001)
  • Bankoff, Greg, George Frerks and Dorothea Hilhorst. 2004. Mapping Vulnerability.Sterling: Earthscan.
  • Blaikie, Piers, Terry Cannon, Ian Davis, and Ben Wisner. 1994. "At Risk: Natural hazards, people's vulnerability, and disasters." New York, NY: Routledge.
  • Kreps, G.A. Ed. 1986. Social Structure and Disaster. Newark: University of Delaware Press.
  • Mileti, Dennis. Disasters by Design: A Reassessment of Natural Hazards in the United States, National Academies Press (1999).
  • Oliver-Smith, Anthony and Susannah M. Hoffman. The Angry Earth: Disaster in Anthropological Perspective, Routledge, 1st edition (1999).
  • United Nations, ISDR: "Living with Risk, a global review of disaster reduction initiatives, United Nations publication (2004)
  • Wade, Nicholas. The New York Times Book of Natural Disasters, The Lyons Press, 1st edition (2001)
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