Hurricane
and typhoon are both names for the same thing but are
used in different parts of the world. The basic term for
both is "tropical cyclone" which is a circular
low-pressure storm over tropical and sub-tropical waters.
If the tropical cyclone has a maximum sustained surface
wind speed of less than 39 mph it is called a tropical
depression. When wind speeds are above 39
mph it is called a tropical storm.
When wind speeds reach 74 mph it is called a hurricane
in the North Atlantic Ocean, the Northeast Pacific Ocean
east of the dateline, or the South Pacific Ocean east
of 160E, a typhoon in the Northwest
Pacific Ocean west of the dateline, a severe
tropical cyclone in the Southwest Pacific
Ocean west of 160E or Southeast Indian Ocean east of 90E,
a severe cyclonic storm in the
North Indian Ocean, and a tropical cyclone
in the Southwest Indian Ocean. Damage
from hurricanes can be caused by wind, flooding caused
by storm surge and flooding caused by rainfall.
It is interesting
to note that in the northern hemisphere cyclonic storms
rotate counter-clockwise (as in the satellite image above)
and clockwise in the southern hemisphere. This is because
of the Coriolis
Effect and has given rise to the incorrect belief
that water drains in sinks and toilets differently in
the northern and southern hemispheres. The Bad
Coriolis site thoroughly covers this myth.
