What is a hurricane?
A hurricane is a powerful tropical storm with sustained winds of at least 119 km/h (74 mph). It forms over warm ocean water and spins around a calm center called the eye.
Hurricanes form over tropical oceans where the water is at least about 26.5 degrees Celsius. Warm, moist air rises, cools and forms clouds, releasing heat that powers the storm. Earth's rotation makes the storm spin, counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.
The same type of storm has different names in different places. It is called a hurricane in the Atlantic and northeastern Pacific, a typhoon in the northwestern Pacific and a cyclone in the South Pacific and Indian Ocean. Hurricanes are rated from Category 1 to Category 5 on the Saffir-Simpson scale, based on wind speed.
Dangers
Hurricanes bring destructive winds, heavy rain, flooding and storm surge, a rise in seawater pushed ashore by the wind. Storm surge is often the deadliest danger. Forecasters use satellites, aircraft and computer models to track storms and warn people days in advance.
Did You Know?
Atlantic hurricanes are given names from lists that repeat every six years. The names of especially deadly storms are retired.