- 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 greater.
- Hurricane/Tropical Storm Watch: Hurricane/tropical storm conditions are possible in the specified area, usually within 36 hours. Be prepared to evacuate.
- Hurricane/Tropical Storm Warning: Hurricane/tropical storm conditions are expected in the specified area, usually within 24 hours. If advised by local authorities to evacuate, leave immediately!
- Tornado Watch: Tornadoes are possible. Remain alert for approaching storms. Watch the sky and stay tuned to NOAA Weather Radio, commercial radio, or television for information.
- Tornado Warning: A tornado has been sighted or indicated by weather radar. Take shelter immediately.
- Flood/Flash Flood Watch: Flooding or flash flooding is possible. Be prepared to move to higher ground.
- Flood Warning: Flooding is occurring or will occur soon; if advised to evacuate, do so immediately.
- Flash Flood Warning: A flash flood is occurring; seek higher ground on foot immediately.
Classification of Hurricanes
Hurricanes are classified into five categories based on wind speed, central pressure, and damage potential. Category Three and higher hurricanes are considered major hurricanes, although Categories One and Two are still extremely dangerous and warrant the public's full attention. This classification is called the Saffir-Simpson Hurricane Wind Scale.
Sustained winds: 74-95 mph
Damage: Minimal - Unanchored mobile homes, vegetation, and signs
Storm Surge: 4-5 ft.
Sustained winds: 96-110 mph
Damage: Moderate - All mobile homes, roofs, small crafts, flooding
Storm Surge: 6-8 ft.
Sustained winds: 111-130 mph
Damage: Extensive - Small buildings, low-lying roads cut off
Storm Surge: 9-12 ft.
Sustained winds: 131-155 mph
Damage: Extreme - Roofs destroyed, trees down, roads cut off, mobile homes destroyed, beach homes flooded
Storm Surge: 13-18 ft.
Sustained winds: Greater than 155 mph
Damage: Catastrophic - Most buildings and vegetation destroyed, major roads cut off, homes flooded
Storm Surge: Greater than 18 ft.
Page last updated: April 13, 2017