Types of Hurricanes

A hurricane is a type of tropical cyclone - an organized rotating weather system that develops in the tropics. Hurricanes rotate counterclockwise in the Northern Hemisphere.

Tropical cyclones are classified as follows:
  • Tropical Depression
    An organized system of persistent clouds and thunderstorms with a closed low-level circulation and maximum sustained winds of 38 mph (33 knots) or less.
  • Tropical Storm
    An organized system of strong thunderstorms with a well defined circulation and maximum sustained winds of 39 to 73 mph (34-63 knots).
  • Hurricane
    An intense tropical weather system with a well defined circulation and sustained winds of 74 mph (64 knots) or higher. In the western North Pacific, hurricanes are called typhoons, and similar storms in the Indian Ocean are called cyclones.
Tropical depressions and tropical storms, while generally less dangerous than hurricanes, still can be deadly. The winds of tropical depressions and tropical storms are usually not the greatest threat. Heavy rains, flooding and severe weather, such as tornadoes, create the greatest threats from tropical storms and depressions.

On average each year, 10 tropical storms, 6 of which become hurricanes,develop in the Atlantic Ocean, Caribbean Sea or Gulf of Mexico. In a typical 3-year span, the U.S. coastline is struck on average five times by hurricanes, two of which will be designated as major hurricanes.

This Info is from the National Weather Service.