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Tropical storms, cyclones, hurricanes and typhoons, although named differently,
describe the same disaster type.
Essentially, these disaster types refer
to a large scale closed circulation system in the atmosphere
which combines low pressure and strong winds that rotate counter
clockwise in the northern hemisphere and clockwise in the
southern hemisphere.
The system is referred to as a "cyclone" in the Indian Ocean and and South Pacific, "hurricane" in the
Western Atlantic and Eastern Pacific and "typhoon" in the Western
Pacific.
Hurricanes and typhoons are the same storm types
as "tropical cyclones" (the local name for storms which originate
in the Caribbean and China Sea region respectively).
A tropical cyclone is a non-frontal storm system that is characterised by a low pressure center, spiral rain bands and strong winds. Usually it originates over tropical or subtropical waters and rotates clockwise in the southern hemisphere and counter-clockwise in the northern hemisphere. The system is fueled by heat released when moist air rises and the water vapor it contains condenses ("warm core" storm system). Therefore the water temperature must be >27 °C.
Cyclones, hurricanes and
typhoons can be predicted several days in advance. The onset
is extensive and often very destructive. These disasters are
usually more destructive than floods.
First, in a sudden, brief
onslaught, high winds cause major damage to infrastructure
and housing, in particular fragile constructions. They are
generally followed by heavy rains and floods and, in flat
coastal areas, by tidal waves.
In the case of cyclones,
accurate landfall predictions can give only a few hours' notice
to threatened populations. In addition, people generally opt
to wait until the very last minute before abandoning their
home and possessions. Deaths from drowning in the high tides
and sudden flooding and material losses are therefore often
very high.
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Disaster management
