Natural disaster

A natural disaster is the effect of a natural hazard (e.g., flood, tornado, hurricane, volcanic eruption, earthquake, or landslide) that affects the environment, and leads to financial, environmental and/or human losses. The resulting loss depends on the capacity of the population to support or resist the disaster, and their resilience.[1] This understanding is concentrated in the formulation: "disasters occur when hazards meet vulnerability."[2] A natural hazard will hence never result in a natural disaster in areas without vulnerability, e.g. strong earthquakes in uninhabited areas. The term natural has consequently been disputed because the events simply are not hazards or disasters without human involvement.[3]

Contents

Natural disasters

Main articles: Disaster and List of natural disasters

Land movement disasters

Avalanches

Avalanche on the backside (East) of Mt. Timpanogos, Utah at Aspen Grove trail

Notable avalanches include:

Earthquakes

An Earthquake is a sudden shake of the Earth's crust caused by the tectonic plates colliding.The vibrations may vary in magnitude. The underground point of origin of the earthquake is called the "focus". The point directly above the focus on the surface is called the"epicenter". Earthquakes by themselves rarely kill people or wildlife. It is usually the secondary events that they trigger, such as building collapse, fires, tsunamis (seismic sea waves) and volcanoes, that are actually the human disaster. Many of these could possibly be avoided by better construction, safety systems, early warning and evacuation planning.Earthquakes are caused by the discharge of accumulated along geologic fault.

Lahars

A lahar is a volcanic mudflow or landslide. The 1953 Tangiwai disaster was caused by a lahar, as was the 1985 Armero tragedy in which the town of Armero was buried and an estimated 23,000 people were killed.

Volcanic eruptions

Pu'u 'Ō'ō

Water disasters

Floods

The Limpopo River, in southern Mozambique, during the 2000 Mozambique flood

Some of the most notable floods include:

Tropical cyclones can result in extensive flooding and storm surge, as happened with:

Limnic eruptions

A cow suffocated by gases from Lake Nyos after a limnic eruption

A limnic eruption occurs when a gas, usually CO2 suddenly erupts from deep lake water, posing the threat of suffocating wildlife, livestock and humans. Such an eruption may also cause tsunamis in the lake as the rising gas displaces water. Scientists believe landslides, volcanic activity, or explosions can trigger such an eruption. To date, only two limnic eruptions have been observed and recorded:

Tsunami

The tsunami caused by the December 26, 2004, earthquake strikes Ao Nang, Thailand.

Tsunamis can be caused by undersea earthquakes as the one caused in Ao Nang, Thailand, by the 2004 Indian Ocean Earthquake, or by landslides such as the one which occurred at Lituya Bay, Alaska.

(This also fits within the "Land movement disaster" category because it started with an earthquake.)

Weather disasters

Young steer after a blizzard, March 1966

Blizzards

Significant blizzards in the United States include:

Cyclonic storms

Main articles: Tropical cyclone and Cyclone

Cyclone, tropical cyclone, hurricane, and typhoon are different names for the same phenomenon a cyclonic storm system that forms over the oceans. 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. Another notable hurricane is Hurricane Katrina which devastated the Gulf Coast of the United States in 2005.

Droughts

Well-known historical droughts include:

Hailstorms

Hailstorms (AKA hailstones) are rain drops that have formed together into ice. A particularly damaging hailstorm hit Munich, Germany, on July 12, 1984, causing about 2 billion of dollars in insurance claims.

Heat waves

The worst heat wave in recent history was the European Heat Wave of 2003.

Hurricane Katrina

A summer heat wave in Victoria, Australia, caused the massive bushfires in 2009. Melbourne experienced three days in a row of temperatures exceeding 40°C. The bushfire, otherwise known as "Black Saturday" was also started intentionally.

Tornadoes

Main article: Tornado

Different Types of Tornadoes:

Supercell Tornadoes

Main article: Supercell

Some of the most violent tornadoes develop from supercell thunderstorms. A supercell thunderstorm is a long-lived thunderstorm possessing within its structure a continuously rotating updraft of air. These storms have the greatest tendency to produce tornadoes, some of the huge wedge shape. The supercell thunderstorm has a low-hanging, rotating layer of cloud known as a "wall cloud." It looks somewhat like a layer of a layer cake that hangs below the broader cloud base. One side of the wall cloud is often rain-free, while the other is neighbored by dense shafts of rain. The rotating updraft of the supercell is seen on radar as a "mesocyclone."

The tornadoes that accompany supercell thunderstorms are more likely to remain in contact with the ground for long periods of time—an hour or more—than other tornadoes, and are more likely to be violent, with winds exceeding-200 mph.

Landspout

Generally weaker than a supercell tornado, a landspout is not associated with a wall cloud or mesocyclone. It may be observed beneath cumulonimbus or towering cumulus clouds and is the land equivalent of a waterspout. It often forms along the leading edge of rain-cooled downdraft air emanating from a thunderstorm, known as a "gust front."

Gustnado

Weak and usually short-lived, a gustnado forms along the gust front of a thunderstorm, appearing as a temporary dust whirl or debris cloud. There may be no apparent connection to or circulation in the cloud aloft. These appear like dust devils.

Waterspout

A waterspout is a tornado over water. A few form from supercell thunderstorms, but many form from weak thunderstorms or rapidly growing cumulus clouds. Waterspouts are usually less intense and causes far less damage. Rarely more than fifty yards wide, it forms over warm tropical ocean waters, although its funnel is made of freshwater droplets condensed from water vapor from condensation - not saltwater from the ocean. Waterspouts usually dissipate upon reaching land.

The following are tornado-like circulations

Dust Devils

Dry, hot, clear days on the desert or over dry land can bring about dust devils. Generally forming in the hot sun during the late morning or early afternoon hours, these mostly harmless whirlwinds are triggered by light desert breezes that create a swirling plume of dust with speeds rarely over 70 mph. These differ from tornadoes in that they are not associated with a thunderstorm (or any cloud), and are usually weaker than the weakest tornado.

Typically, the life cycle of a dust devil is a few minutes or less, although they can last much longer. Although usually harmless, they have been known to cause minor damage. They can blow vehicles off the road and could damage your eyes by blowing dust into them.

Firewhirls

Sometimes the intense heat created by a major forest fire or volcanic eruption can create what is known as a firewhirl, a tornado-like rotating column of smoke and/or fire. This happens when the fire updraft concentrates some initial weak whirl or eddy in the wind. Winds associated with firewhirls have been estimated at over 100 mph. They are sometimes called fire tornadoes, fire devils, or even firenadoes.[4]

Fire

Wildfires are an uncontrolled fire burning in wildland areas. Common causes include lightning and drought but wildfires may also be started by human negligence or arson. They can be a threat to those in rural areas and also wildlife.

A notable case of wildfire was the 2009 Victorian bushfires in Australia.

Nine elderly Russians have died in a blaze at a nursing home that may have been started by a resident setting himself on fire.The fire at the facility in Tver, northeast of Moscow, injured two others and forced the evacuation of some 480 people early on Monday,and investigators found a canister of flammable liquid in the room where the fire started, leading to speculation the resident set himself ablaze.

Health and diseases

Epidemic

The A H5N1 virus, which causes Avian influenza

An epidemic is an outbreak of a contractible disease that spreads at a rapid rate through a human population. A pandemic is an epidemic whose spread is global. There have been many epidemics throughout history, such as Black Death. In the last hundred years, significant pandemics include:

Other diseases that spread more slowly, but are still considered to be global health emergencies by the WHO include:

Famine

In modern times, famine has hit Sub-Saharan Africa

Space

Fallen trees caused by the Tunguska meteoroid of the Tunguska event in June 1908.

Gamma ray bursts

Main article: gamma ray burst

Impact events

Main article: impact event

One of the largest impact events in modern times was the Tunguska event in June 1908.

Solar flares

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. Some known solar flares include:

Supernovae and hypernovae

Main articles: supernova and hypernova

Future of natural disasters

The United Kingdom based charity Oxfam publicly stated that the number of people hit by climate-related disasters is expected to rise by about 50%, to reach 375 million a year by 2015.[5]

Insurance

Natural disasters play a major role in the insurance industry, which pays for certain damages arising from hurricanes, wildfires, and other catastrophes. Large reinsurance companies are particularly involved.[6]

See also

References

  1. ↑ G. Bankoff, G. Frerks, D. Hilhorst (eds.) (2003). Mapping Vulnerability: Disasters, Development and People. ISBN ISBN 1-85383-964-7. 
  2. ↑ B. Wisner, P. Blaikie, T. Cannon, and I. Davis (2004). At Risk - Natural hazards, people's vulnerability and disasters. Wiltshire: Routledge. ISBN ISBN 0-415-25216-4. 
  3. ↑ D. Alexander (2002). Principles of Emergency planning and Management. Harpended: Terra publishing. ISBN ISBN 1-903544-10-6. 
  4. ↑ Weather Encyclopedia, The Weather Channel, Accessed on June 2, 2009, http://www.theweatherchannelkids.com.
  5. ↑ BBC: Oxfam warns of climate disasters
  6. ↑ III. (2008). 2008 Natural Catastrophe Review.

External links