Hurricanes are giant tropical storms that produce heavy rainfall and super-strong winds.
Hurricanes form over warm ocean waters near the equator. The warm, moist air above the ocean surface rises, causing air from surrounding areas to be 'sucked' in. This 'new' air then becomes warm and moist, and rises, too, beginning a continuous cycle that forms clouds. The clouds then rotate with the spin of the Earth. If there is enough warm water to feed the storm, a hurricane forms!
Hurricanes rotate around a circular centre called the 'eye', where it is generally calm with no clouds. Surrounding the eye is the eye wall - the most dangerous part of the hurricane with the strongest winds, thickest clouds and heaviest rain!
Most hurricanes occur harmlessly out at sea. However, when they move towards land they can be incredibly dangerous and cause serious damage.
The strong spiralling winds of a hurricane can reach speeds of up to 320kmph - strong enough to rip up entire trees and destroy buildings!
The scientific name for a hurricane is a tropical cyclone. Tropical cyclones go by different names in different places. In North America and the Caribbean they are called "hurricanes", in the Indian Ocean they are called "cyclones", and in Southeast Asia they are called "typhoons."
In the southern hemisphere, hurricanes rotate in a clockwise direction, and in the northern hemisphere they rotate in an anti-clockwise direction. This is due to what's called the Coriolis Force, produced by the Earth's rotation.
When a hurricane reaches land it often produces a 'storm surge'. This is when the high winds drive the sea toward the shore, causing water levels to rise and creating large crashing waves. Storm surges can reach 6m high and extend to over 150km! Hurricanes also cause damage with high speed winds that can blow down trees and damage homes. Many hurricanes can develop several small tornados as well.
The largest hurricane on record is Typhoon Tip, which occurred in 1979 in the northwest Pacific. With a diameter of around 2 220km, it was nearly half the size of the United States!
Hurricanes that form in the Caribbean and the Atlantic Ocean occur between June 1st and November 30th each year. This is called hurricane season.
Hurricanes are given names by the World Meteorological Organisation (WMO) so that they can be distinguished. Each year, tropical storms are named in alphabetical order according to a list produced by the WMO. That name stays with the storm if it develops into a hurricane. The names can only be repeated after six years.
DURING A HURRICANE WATCH
A hurricane watch is issued when there is a threat of hurricane conditions within 24-36 hours.
Listen to a battery-operated radio or television for hurricane progress reports.