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Hurricanes
Introduction on Hurricanes
Hurricanes are tropical cyclones that rotate counterclockwise with wind speeds in excess of 74 mph.
Most hurricanes form over warm seas near the equator. They are created when the sun heats the ocean surface, causing heated water vapor to rise, condense, and form clouds. These clouds begin to spiral as the earth rotates. More air is pulled underneath and a large vortex is formed.
On average, six Atlantic hurricanes develop each year. When a hurricane moves toward coastal areas it often causes severe damage. Strong winds create storm surges, floods, rip tides and even spawn tornadoes. As the hurricane moves forward, its right front quadrant is typically where the most devastation occurs.
Hurricane Season begins June 1st and continues through November 30th. Be sure to practice hurricane preparedness and learn about hurricane safety and survival.
Hurricane Basics
The Saffir-Simpson Scale:
The National Oceanic and Atmospheric Administration (NOAA) uses this disaster potential scale. There are five categories, one being the least potential damage and five being the worst. Every hurricane is a potential threat to life and property. The category of the storm does not directly relate to the damage it will inflict. It is imperative to take every storm seriously.
| Category |
Wind Speeds |
Storm Surge |
Effects |
| 1 |
74 - 95 mph |
4 - 5 ft. |
Minor Damage |
| 2 |
96 - 110 mph |
6 - 8 ft. |
Major Damage |
| 3 |
111 - 130 mph |
9 - 12 ft. |
Extensive Damage |
| 4 |
131 - 154 mph |
13 - 18 ft. |
Extreme Damage |
| 5 |
155 + mph |
19 - 25 ft. |
Catastrophic Damage |
Storm Terminology:
Tropical Disturbance: A moving area of thunderstorms in the tropics.
Tropical Wave: A westward-moving, low-pressure trough in the deep easterly current that tends to organize low-level circulation. It sometimes travels thousands of miles with little change in shape, producing showers and thunderstorms along its path.
Tropical Depression: An area of low pressure, rotary circulation of clouds and winds up to 38 miles per hour.
Tropical Storm: Counterclockwise circulation of clouds and winds (develops over warm tropical waters) with wind speeds ranging from 39-73 miles per hour. At this stage, the storm is assigned a name.
Hurricane: A tropical storm with wind speeds of 74 miles per hour or more, and dangerously high water and waves.
“Eye” of the Hurricane: The relatively calm area near the center of the storm where winds are light and the sky often is partly cloudy. The calm area is deceptive because it is bordered by maximum-force winds and torrential rains; it can last from several minutes to more than an hour.
Storm Surge: An abnormal rise in sea level produced by the strong winds and low pressure within a hurricane. The storm surge occurs in the right half of the storm as it makes landfall. The storm surge potentially could elevate sea level from 2-20 feet. (9 out of 10 hurricane-related deaths occur as a result of storm surge rather than winds.) For more information about storm surge, visit
Advisory: Hurricane and storm information delivered to the public every six hours.
Intermediate Advisory: Hurricane and storm information updated every 2-3 hours, or as necessary.
Special Advisory: Hurricane and storm information delivered when there is a significant change in storm-related weather conditions or warnings.
Gale Warning: An advisory that 39-54 mph sustained winds and strong wave action are expected.
Storm Warning: An advisory that 55-73 mph sustained winds and strong wave action are expected.
Hurricane Watch: An announcement of possible hurricane conditions, for a particular area, within 36 hours.
Hurricane Warning: An advisory that a hurricane is expected to strike a specified area within 24 hours or less.
2009 - 2013 Storm Names |
