Disasters

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Disasters

• Prepared by Arthur Puzinas

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Disasters (disambiguation)

• A disaster (from Middle French désastre, from Old
  Italian disastro, from Latin pejorative prefix
  dis- bad astrum star) is the impact of a
  natural or man-made hazard that negatively
  affects society or environment. Disasters occur
  when hazards strike in vulnerable areas.
  Disasters are generally more limited in scale
  than doomsday events, the global impact of which
  would threaten a large proportion of life on
  earth. The word disaster's root is from
  astrology this implies that when the stars are
  in a bad position a bad event will happen.

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Sorts of natural disasters

• They are avalanche, cold, drought, earthquake,
  epidemics, fire, famine, flood, hail, heat,
  landslide, limnic eruption, sinkhole, solar
  flare, storm surge, thunderstorm, tornado,
  tropical cyclones, tsunami, volcanic eruption,
  waterspout and winter storm.

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The Avalanche

• An avalanche is a very large slide of snow (or
  rock) down a mountainside, caused when a buildup
  of snow is released down a slope, and is one of
  the major dangers faced in the mountains. An
  avalanche consists of rapidly moving granular
  material that has exceeded the critical static
  friction threshold and thereby causes additional
  material to exceed it's threshold as well, in a
  cascading effect.
• In an avalanche, lots of material or mixtures of
  different types of material fall or slide rapidly
  under the force of gravity. Avalanches are often
  classified by what they are made of, for example
  snow, ice, rock or soil avalanches. A mixture of
  these would be called a debris avalanche.
• A large avalanche can run for many 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 (60 mph). It killed 12 people in
  their chalets under 100,000 tons of snow, 5
  meters (15 feet) deep. The Mayor of Chamonix was
  convicted of second-degree murder for not
  evacuating the area, but received a suspended
  sentence1.

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The Drought

• A drought is a period of time when there is not
  enough water to support agricultural, urban or
  environmental water needs. A drought usually
  refers to an extended period of below-normal
  rainfall, but can also be caused by drying bores
  or lakes, or anything that reduces the amount of
  liquid water available. Although what is
  considered "normal" varies from one region to
  another, drought is a recurring feature of nearly
  all the world's climatic regions. The effects of
  drought vary greatly, depending on agricultural,
  urban and environmental water needs. And in Which
  water companies,and farmers suffer.

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The Flood

• A flood (in Old English flod, a word common to
  Teutonic languages compare German Flut, Dutch
  vloed from the same root as is seen in flow,
  float) is an overflow of water, an expanse of
  water submerging land, a deluge.1 In the sense
  of "flowing water", the word is applied to the
  inflow of the tide, as opposed to the outflow or
  "ebb". The Flood, the great Universal Deluge of
  myth and perhaps of history is treated at Deluge
  in mythology. Floods from the sea can cause
  overflow or overtopping of flood-defenses like
  dikes as well as flattening of dunes or bluffs.
  Land behind the coastal defence may be inundated
  or experience damage. A flood from sea may be
  caused by a heavy storm (storm surge), a high
  tide, a tsunami, or a combination thereof. As
  many urban communities are located near the coast
  this is a major threat around the world. Many
  rivers flow over relatively flat land border on
  broad flood plains. When heavy the deposition of
  silt on the rich farmlands and can result in
  their eventual depletion. The annual cycle of
  flood and farming was of great significance to
  many early farming cultures, most famously to the
  ancient Egyptians of the Nile river and to the
  Mesopotamians of the Tigris and Euphrates rivers.
• A flood happens when an area of land, usually
  low-lying, is covered with water. The worst
  floods usually occur when a river overflows its
  banks. An example of this is the January 1999
  Queensland floods, which swamped south-eastern
  Queensland. Floods happen when soil and
  vegetation cannot absorb all the water. The water
  then runs off the land in quantities that cannot
  be carried in stream channels or kept in natural
  ponds or man-made reservoirs.

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Limnic Eruption

• A limnic eruption, also referred to as a lake
  overturn or exploding lake, is a rare type of
  natural disaster in which 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 CO2 displaces water. Scientists
  believe landslides, volcanic activity, or
  explosions can trigger such an eruption. Some
  features of limnically active lakes include
• CO2-saturated incoming water
• A cool lake bottom indicating an absence of
  direct volcanic interaction with lake waters
• An upper and lower thermal layer with differing
  CO2 saturations
• Close proximity to areas with volcanic activity
• Scientists have recently determined, from
  investigations into the mass casualties in the
  1980s at Lake Monoun and Lake Nyos, that limnic
  eruptions and volcanic eruptions, although
  indirectly related, are actually separate types
  of disaster events.

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Tropical Cyclones

• A tropical cyclone is a warm storm system fueled
  by thunderstorms near its center. It feeds on the
  heat released when moist air rises and the water
  vapor in it condenses. The term describes the
  storm's origin in the tropics and its cyclonic
  nature, which means that its circulation is
  counterclockwise in the Northern Hemisphere and
  clockwise in the Southern Hemisphere. Tropical
  cyclones are distinguished from other cyclonic
  windstorms such as nor'easters, European
  windstorms, and polar lows by the heat mechanism
  that fuels them, which makes them "warm core"
  storm systems. Depending on their location and
  strength, there are various terms by which
  tropical cyclones are known, such as hurricane,
  typhoon, tropical storm, cyclonic storm, and
  tropical depression.
• Tropical cyclones can produce extremely strong
  winds, tornadoes, torrential rain, high waves,
  and storm surge. They are born and sustained over
  large bodies of warm water, and lose their
  strength over land. This is the reason coastal
  regions can receive significant damage from a
  tropical cyclone, while inland regions are
  relatively safe from receiving strong winds.
  Heavy rains, however, can produce significant
  flooding inland, and storm surges can produce
  extensive coastal flooding up to 25 miles/40 km
  inland. Although their effects on human
  populations can be devastating, tropical cyclones
  can also relieve drought conditions. They carry
  heat away from the tropics, an important
  mechanism of the global atmospheric circulation
  that helps maintain equilibrium in the Earth's
  troposphere.

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