Provided by NOAA’s
National Weather Service
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.
What to listen for:
- Hurricane/Tropical Storm Watch: Hurricane/tropical storm conditions are possible in the specified area of the Watch, usually within 36 hours. During a Watch, prepare your home and review your plan for evacuation in case a Hurricane/Tropical Storm Warning is issued.
- Hurricane/Tropical Storm Warning: Hurricane/tropical storm conditions are expected in the specified area of the Warning, usually within 24 hours. Complete storm preparations and leave the threatened area if directed by local officials.
- Short Term Watches and Warnings: Hurricane/tropical storm conditions are expected in the specified area of the Warning, usually within 24 hours. Complete storm preparations and leave the threatened area if directed by local officials.
- Flood Watch: This product informs the public and cooperating agencies of possible flooding. If you are in a Watch area, check flood action plans, keep informed and be ready to act if a warning is issued or you see flooding.
- Flood/Flash Flood Warning: A flood/flash flood Warning is issued for specific communities, streams or areas where flooding is imminent or in progress. Persons in the warning area should take precautions IMMEDIATELY!
If you are asked to leave an area due to an imminent Hurricane or Tropical Storm:
- DON’T delay or doubt.
- DO leave IMMEDIATELY!