Born from Warm Water

A hurricane begins as a cluster of thunderstorms over tropical ocean water that is at least 26.5 degrees Celsius. Warm water evaporates, rises, and releases heat as it condenses into clouds. This heat fuels the storm. The warmer the water, the more fuel available.

The Earth's rotation bends the rising air into a spinning vortex through the Coriolis effect. In the Northern Hemisphere, hurricanes spin counterclockwise; in the Southern Hemisphere, clockwise. At the center sits the eye — a calm, clear column surrounded by the eyewall, where the most violent winds occur. When the eye passes overhead, the calm is only a pause: the far side of the eyewall is still coming, with winds blowing from the opposite direction.