Hurricanes striking the eastern United States typically form in equatorial waters from Africa to the Caribbean. Hurricanes in the northern hemisphere spin counterclockwise as they cross the Atlantic toward the U.S.
Warm, moist air rises from the ocean surface to cold air above. The water condenses, forming thunderstorms.
Wind increases in speed and rotates around a center. The National Hurricane Center begins tracking and forecasting at this stage.
When winds reach 39 mph, the storm is named to identify it. At 74 mph, the storm becomes a hurricane.