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Before the Storm

Hurricane Hazards

Hurricanes can combine storm surge, powerful winds, tornadoes and torrential rains into a devastating combination.

Storm Surge. Storm surge is an abnormal rise in sea level 50 to 100 miles wide that sweeps across the coast near where the "eye" of the hurricane makes landfall. The surge of high water, topped by waves, is devastating. Along the immediate coast, storm surge is the greatest threat to life and property. Most hurricane-related deaths are caused by drowning.

Winds. Hurricane force winds, 74 mph or more, can destroy buildings and mobile homes. Debris can become flying missiles in hurricanes. Winds often stay above hurricane strength well inland. If you do not have to evacuate, it is extremely important to secure your home and cover your windows before the storm. Remember, mobile homes are extremely vulnerable to high winds and should be evacuated.

Heavy Rains and Floods. Widespread torrential rains often in excess of 10 inches can accompany a hurricane and can produce destructive floods. This is a major threat to areas well inland.

Tornadoes. Hurricanes also produce tornadoes, which add to the hurricane's destructive power.

Hurricane Warnings and Advisories

Tropical Depression. A disturbance with a clearly defined low pressure area; high wind speed is 38 mph.

Tropical Storm: A distinct low pressure area defined by a counterclockwise rotating circulation with winds of 39 - 73 mph.

Hurricane. Once a tropical storm's constant wind and speed reaches 74 mph or greater, it is classified as a hurricane. In the western Pacific hurricanes are called typhoons. Similar storms in the Indian Ocean are called cyclones.

Tropical Storm Watch. An alert for a specific area that a tropical storm may pose a threat within 36 hours

Tropical Storm Warning. An alert that tropical storm conditions, including sustained winds of 39 to 73 mph are expected in specific areas within 24 hours.

Hurricane Watch. An alert for specific areas that hurricane conditions pose a threat to an area within 36 hours.

Hurricane Warning. An issued when hurricane conditions (winds of 74 miles per hour or greater, or dangerously high water and rough seas) are expected in 24 hours or less. All precautions should be completed immediately.

Evacuation Order. The most important instruction you will receive. Once issued, an evacuation order is mandatory.

Hurricane Categories and Evacuation Zones

Find Your Evacuation Zone

Meteorologists classify hurricanes by categories of 1-5 using a scale that measures the wind and speed of the storm.
    A Tropical Depression has a highest wind speed of 38 miles per hour (33 knots), with some rotary circulation and one or more closed isobars.
    A Tropical Storm has distinct rotary circulation with wind speeds of 39- 73 miles per hour (34-63 knots), closed isobars and a pressure of 14.0 pounds per square foot.
    A Hurricane has strong and very pronounced rotary circulation, closed isobars, a pressure of 17 or more pounds per square foot and winds of 74 miles per hour (64 knots) and higher.
    The devastating class 5 hurricane exceeds wind speed of 156 miles per hour.