A hurricane is an intense, rotating oceanic weather system that possesses maximum sustained winds exceeding 119 km/hr (74 mph). It forms and intensifies over tropical oceanic regions.
Hurricanes are generally smaller than storms in mid-latitudes, typically about 500 km (311 miles) in diameter. At the ocean’s surface, the air spirals inward in a counterclockwise direction. This cyclonic circulation becomes weaker with height, eventually turning into clockwise (anticyclonic) outflow near the top of the storm.