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Hurricane Terms

Category One - Sustained hurricane winds of 74-95 mph. Example: Hurricane Irma, 2017

Category Two - Sustained hurricane winds of 96-110 mph. Example: Hurricane Wilma, 2005

Category Three - Sustained hurricane winds of 111-130 mph. Example: Hurricane Frances, 2004

Category Four - Sustained hurricane winds of 131-155 mph. Example: Hurricane Charley, 2004

Category Five - Sustained hurricane winds greater than 155 mph. Example: Hurricane Andrew, 1992

For more details about each category, go to Saffir-Simpson Hurricane Wind Scale.

Evacuation - A warning to persons who may be at risk, due to location or other vulnerabilities, within a designated area that a threat to life and property may be imminent and they should move to a safer location as directed by emergency management officials.

Hurricane - A tropical system with maximum sustained winds of 74 mph or higher.

Hurricane Eye - The calm center of the storm that is often only partly covered by clouds.

Hurricane Warning - A warning that hurricane conditions, including sustained winds of 74 mph or higher, are imminent within 36 hours or less.

Hurricane Watch - An announcement that hurricane conditions, including sustained winds of more than 74 mph, are possible within 48 hours.

Mandatory Evacuation - A notification to persons within a designated area (evacuation zone) that an imminent threat to life and property exists. Individuals MUST relocate and seek refuge in an inland, non-evacuation area.

Saffir-Simpson Scale - A categorical one-to-five rating based on a hurricane's maximum sustained wind speed. The scale also estimates potential property damage. Go to Saffir-Simpson Hurricane Wind Scale to learn more.

Storm Surge - An abnormal rise in sea level accompanying a hurricane or other intense storm that's caused by storm's barometric pressure, forward speed and wind intensity. Surge can be anywhere from a few feet to 18 feet along South Florida coasts. Storm Surge watches and warnings are issued to the public by the National Hurricane Center.

Storm Surge Watch - The possibility of life-threatening inundation of rising water moving inland from the shoreline within the specified areas within 48 hours.

Storm Surge Warning - The possibility of life-threatening inundation of rising water moving inland from the shoreline within the specified areas within 36 hours.

Tropical Depression - A tropical system with maximum sustained winds of 38 mph or less. Tropical depressions can produce heavy rainfall.

Tropical Storm - A tropical system with sustained winds of 39-78 mph. A tropical storm can produce heavy rainfall and strong winds.

Tropical Storm Warning - A warning that tropical storm conditions, including sustained winds of 39-73 mph, are imminent within 36 hours.

Tropical Storm Watch - An announcement that tropical storm conditions, including sustained winds of 39-73 mph, are possible within 48 hours.