 Hurricane Guide
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Hurricane Intensities
A hurricane is a type of tropical cyclone, the generic term for a low pressure system that generally forms in the tropics. A typical cyclone is accompanied by thunderstorms, and in the Northern Hemisphere, a counterclockwise circulation of winds near the earth's surface. All Atlantic and Gulf of Mexico coastal areas are subject to hurricanes or tropical storms.
The Atlantic hurricane season lasts from June to November, with the peak season from mid-August to late October. Hurricanes can cause catastrophic damage to coastlines and several hundred miles inland. Winds can exceed 155 miles per hour. Hurricanes and tropical storms can also spawn tornadoes and microbursts, create storm surges along the coast, and cause extensive damage from heavy rainfall.
Hurricanes are classified into five categories based on their wind speed, central pressure, and damage potential. Category Three and higher hurricanes are considered major hurricanes, though Categories One and Two are still extremely dangerous and warrant your full attention.
Saffir-Simpson Hurricane Scale
Category 1 : Sustained Winds of 74-95 (mph) : Minimal Damage : Storm Surge of 4-5 feet
Category 2 : Sustained Winds of 96-110 (mph) : Moderate Damage : Storm Surge of 6-8 feet
Category 3 : Sustained Winds of 111-130 (mph) : Extensive Damage : Storm Surge of 9-12 feet
Category 4 : Sustained Winds of 131-155 (mph) : Extreme Damage : Storm Surge of 13-18 feet
Category 5 : Sustained Winds of more than 155 (mph) : Catastrophic Damage : Storm Surge +18 feet
Hurricane Terms
Tropical Depression
An organized system of clouds and thunderstorms with a defined surface circulation and maximum sustained winds of 38 MPH (33 knots) or less. Sustained winds are defined as one-minute average wind measured at about 33 ft (10 meters) above the surface.
Tropical Storm
An organized system of strong thunderstorms with a defined surface circulation and maximum sustained winds of 39-73 MPH (34-63 knots).
Hurricane
An intense tropical weather system of strong thunderstorms with a well-defined surface circulation and maximum sustained winds of 74 MPH (64 knots) or higher.
Storm Surge
A dome of water pushed onshore by hurricane and tropical storm winds. Storm surges can reach 25 feet high and be 50-1000 miles wide.
Storm Tide
A combination of storm surge and the normal tide (i.e., a 15-foot storm surge combined with a 2-foot normal high tide over the mean sea level created a 17-foot storm tide).
Hurricane/Tropical Storm Watch
Hurricane/tropical storm conditions are possible in the specified area, usually within 36 hours. Tune in to NOAA Weather Radio, commercial radio, or television for information.
Hurricane/Tropical Storm Warning
Hurricane/tropical storm conditions are expected in the specified area, usually within 24 hours.
Short Term Watches and Warnings
These warnings provide detailed information about specific hurricane threats, such as flash floods and tornadoes.
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