The Online Encyclopedia and Dictionary







A disaster is a natural or man-made event that negatively affects life, property, livelihood or industry often resulting in permanent changes to human societies, ecosystems and environment. Disasters manifest as hazards exacerbating vulnerable conditions and exceeding individuals' and communities' means to survive and thrive. Most events included herein are compiled from United States Federal Emergency Management Agency and Department of Homeland Security. [1][2]

According to the Word Detective the word disaster appeared in the 16th century and derives from the Latin "away," "wrong" or "not", and "aster", meaning "star". Its roots imply that when the stars are in a bad position, a disaster is about to happen.[3]

The Univeristy of Delaware's Disaster Research Center differentiates disasters from emergencies and catastrophes as follows:

  • Emergency: An event that may be managed locally without the need of added response measures or changes to procedure.
  • Disaster: An event that,
  1. involves more groups who normally do not need to interact in order to manage emergencies
  2. requires involved parties to relinquish the usual autonomy & freedom to special response measures and organizations
  3. changes the usual performance measures, and
  4. requires closer operations between public and private organizations.
  1. destroys most of a community
  2. prevents local officials performing their duties
  3. causes most community functions cease, and
  4. prevents adjacent communities from providing aid. [4]


Natural disasters

A Natural phenomenon can easily turn into a natural disaster. Appearing to arise without direct human involvement, natural disasters are sometimes called an act of God. A natural disaster may become more severe because of human actions prior, during or after the disaster itself. A specific disaster may spawn different types of events and may reduce the survivability of the initial event. A classic example, is an earthquake that collapses homes, trapping people and breaking gas mains that then ignite, and burn people alive while trapped under debris. Human activity in risk areas may cause natural disasters. Volcanos are particularly prone to causing other events like fires, lahars, mudflowed, landslides, earthquakes, and tsunamis.


An avalanche is a slippage of built-up snow down an incline, possibly mixed with ice, rock, soil or plantlife in what is called a debris avalanche. Avalanches are categoried as either a slab or powder avalanche. Avalanches are a major danger in the mountains during the winter as a large one can run for miles, and can create massive destruction of the lower forest and anything else in its path. For example, in Montroc, France , in 1999 300,000 cubic metres of snow slid on a 30 degree slope, achieving a speed of 100 km/h. It killed 12 people in their chalets under 100,000 tons of snow, 5 meters deep. The Mayor of Chamonix was charged with manslaughter. [5]


Extreme cold snaps are hazardous to humans and their livestock. In a 2003 Mongolian cold snap, almost 30,000 livestock animals perished due to excessive snow and cold. When the temperature drops, caloric intake must increase to maintain body heat to for shivering [6]. Cold, especially in combination with other inclement weather is especially deadly [7].


Disease becomes a disaster when it spreads in a pandemic or epidemic as a massive outbreak of an infectious agent. Disease 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, it killed 25-40 million people. The Black Death, which occurred in the 14th Century, killed over 20 million people, one third of Europe's population. Plant and animal life may also be affected by disease epidemics and pandemics.


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.


San Francisco
San Francisco

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 line, and are unpredictable. They are capable of killing hundreds of thousands of people, such as in the 1976 Tangshan and 2004 Indian Ocean earthquakes.


Forest fire
Forest fire

A fire is a natural disaster that may destroy ecosystems like grasslands, forests causing great loss of life, property, livestock and wildlife. Bush and 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. Some of the biggest city fires are The Great Chicago Fire, The Great Fire of London, and The San Fransisco Fire. [8]


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.


North Carolina 1916
North Carolina 1916

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. A river which floods particularly often is the Huang He in China, and a particularly damaging flood was the Great Flood of 1993.



A hailstorm is a natural disaster where a thunderstorm produces a numerous amount of 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. Skeleton Lake was named so after 300-600 people were killed by a hailstorm.


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.


A hurricane is a low-pressure 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 most damaging hurricane ever was Hurricane Andrew, which hit southern Florida in 1992.

Limnic eruption

Lake Nyos, Cameroon
Lake Nyos, Cameroon

A sudden release of asphyxiating or inflammable gas from a lake. Three lakes are at risk of limnic eruptions, Lake Nyos, Lake Manoun , and Lake Kivu. A 1986 limnic eruption of 1.6 million tonnes of CO2 from Lake Nyos suffocated 1,800 people in a 20 mile radius. In 1984, a sudden outgassing of CO2 had occurred at Lake Manoun, killing 37 local residents. Lake Kivu, with concentrations of methane and CO2, has not experienced a limnic eruption during recorded history, but is suspected of having periodic eruptions every 1,000 years.


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.


A mudslide is a slippage of mud because of poor drainage of rainfall through soil. An underlying cause is often deforestation or lack of vegatation. Some mudslides are massive and can decimate large areas. On January 10, 2005 at 1:20pm in La Conchita, a massive mudslide buried four blocks of the town in over 30 feet of earth. Ten people were killed by the slide and 14 were injured. Of the 166 homes in the community, fifteen were destroyed and 16 more were tagged by the county as uninhabitable.

Sink hole

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.

Solar flare

Solar flare

A solar flare is a violent explosion in the Sun's atmosphere with an energy equivalent to tens of millions of hydrogen bombs. Solar flares take place in the solar corona and chromosphere, heating the gas to tens of millions of kelvins and accelerating electrons, protons and heavier ions to near the speed of light. They produce electromagnetic radiation across the spectrum at all wavelengths from long-wave radio signals to the shortest wavelength gamma rays. Solar flare emmissions are a danger to orbitting satellites, manned space missions, communications systems, and power grid systems.[9]

Storm surge

A storm surge is an onshore rush of water associated with a low pressure weather system, typically a tropical cyclone. Storm surge is caused primarily by high winds pushing on the ocean's surface. The wind causes the water to pile up higher than the ordinary sea level. Storm surges are particularly damaging when they occur at the time of a high tide, combining the effects of the surge and the tide. The highest storm surge ever recorded was produced by the 1899 Bathurst Bay Hurricane, which caused a 13 m (43 feet) storm surge at Bathurst Bay , Australia. In the US, the greatest recorded storm surge was generated by Hurricane Camille, which produced a storm surge in excess of 25 feet (7.6 m).


A thunderstorm is a form of severe weather characterized by the presence of lightning and its attendant thunder, often accompanied by copious rainfall, hail and on occasion snowfall and tornadoes.



A tornado is a natural disaster resulting from a thunderstorm. Tornadoes are violent currents of wind which can blow at up to 318mph. Tornadoes can occur one at a time, or can occur in large tornado outbreaks along a squall line. The worst 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 and was the strongest ever recorded.


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 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.

Volcanic eruption

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. Recent large volcanic eruptions include that of Mount St. Helens and Krakatoa, occurring in 1980 and 1883, respectively.


A waterspout is a torandic weather phenomena normally occurring over tropical waters in light rain conditions. They form at the base of cumulus-type clouds, extend to the water surface where winds pick up water spray. Waterspouts are dangerous to boats, planes and land structures. Many waterspount occur in the Bermuda Triangle and are suspected of being the a cause of the many missing ships and planes in that region.

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.

Man-made disasters

Disasters having an element of human intent, negligence, error or involve a failure of a system are called man-made disasters. Man-made disasters like power or telecommunication outages may be caused by thunderstorms, tornados or earthquakes and though the root cause is an act of God, they are considered a man-made disaster. The power grid and telecommunication infrastructure could be made more resilient against outages however, probably due to cost and feasibilit constraints, the systems were intentionally left vulnerable to outage.


Arson is the criminal intent of setting a fire with intent to cause damage. The definition of arson was originally limited to setting fire to buildings, but was later expanded to include other objects, such as bridges, vehicles, and private property. Arson is the greatest cause of fires in data repositories. [10]

Civil disorder

Civil disorder is a broad term that is typically used by law enforcement to describe one or more forms of disturbance. Examples of disasterous civil disorder include, but are not necessarily limited to: riots; sabotage; and other forms of crime. Although civil disorder does not necessarily escalate to a disaster in all cases the event may escalate into general chaos.


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Data loss

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Dam failure

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Hazardous materials

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Processing interruption

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Liquidity shortage

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Nuclear blast

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Power outage

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Public relations crisis

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Telecommunication outage

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Surviving a disaster

Chances of survival after a disaster is greatly improved when people, local governments and emergency services, businesses and national governments prepare survival plans and assemble survival gear beforehand. What constitutes sufficient preparation is highly dependant on the location and the disasters that are likely to occur in the area.

Personal and family disaster preparation

People and families should make an assessment the likely threats in their location and prepare emergency supply kits , learn basic first aid and decide on 'safe' meeting places.

Young children should be trained to:

  • recognize the warning signs for dangerous situations
  • respond safely to different threats
  • evacuate to a safe place
  • know their full name
  • know their parent's full name
  • know their telephone number
  • know their address
  • know the names of their relatives

Emergency supply kits should include the basic items recommended in the links provided below in addition to any special needs like diapers for babies, prescribed medicines or glasses for those who need them.

Local government and emergency services disaster preparation and management

Local governments and emergency service organizations maintain disaster response plans to minimize further death and property loss with quick and efficient action. A predetermined command structure containing the functions, names, telephone numbers, and addresses needed for a disaster are used to mobilize local police, fire and medical forces (occasionally supported by military forces). A disaster command structure attempts to quickly establish control over a disaster scene to rescue victims, clear casualties and where possible, subdue the threat. Governments may also provide basic humanitarian assistance.

Business disaster preparation and management

To minimize losses and the death or injury of staff, businesses can create a business continuity plan and restore key business functions quickly. Like local government, business should maintain a predetermined command structure in addition to the steps required to restore data and resume business operations.

Businesses also must consider non-traditional threats like liquidity shortages, public relations, power outage and telecommunication outage as a part of their plans.

National disaster preparation

National governments maintain disaster response plans to support local governments and to isolate an event's effects to a localized area. Naturally occurring diseases, biological terrorism, and crop blights are examples of events that may be containable to a small area. A predetermined command structure which may include specialized agencies like the United States Federal Emergency Management Agency aids disaster relief and support of the local governments and emergency services.

Since nations have direct command control over military forces, they may choose to deploy personnel as requested or needed to assist in rescue, treatment of victims, humanitarian aid, and the maintaining of civil order. Generally speaking, national governments can coordinate the deployment of emergency services personnel from unaffected areas to reduce the administrative burden on local command structures. Also, national governments generally have more resources and funds to assist local governments with relief efforts.

Humanitarian disaster preparation

For larger disasters that overwhelm the affected governments, international non-governmental humanitarian agencies may mobilize to offer water, food, housing and medical and psychological treatment of disaster victims. Humanitarian aid may also include long-term recovery and rebuilding efforts.

Information security disaster preparation

Adherence to accepted information security principals require disaster recovery plans. A disaster is the start of a 'crisis' where predefined crisis management plans activate. During the development of the crisis management plan, minimum thresholds are established against which a disaster's effect can be compared. Once a disaster sufficiently interrupts key functions and processes, recovery activities can be initiated to control expectancy loss.

See also


External links

Last updated: 06-01-2005 22:43:14
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