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Saffir/SimpsonScale |
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Hurricanes, no matter how weak, are dangerous. The combination of storm surge, wind and other contributing factors determine a hurricane’s destructive power. In order to compare the disaster potential of hurricanes, emergency forces utilize a scale that helps them predict potential hazards. The National Oceanic and Atmospheric Administration forecasters use the Saffir/Simpson Scale to assign hurricanes to five categories: Category 1 a minimum hurricane, and Category 5 is the most severe or intense. The criteria for each category is described below
Category1
74-95 MPH
Damage to buildings is slight. Manufactured homes that are unanchored along with shrubbery and trees sustain some damage. Some minor pier damage occurs along with coastal road flooding.
Category2
96-110 MPH
Some damage to buildings occurs, such as roofing materials, doors and windows. A considerable amount of damage happens to vegetation, unanchored manufactured homes and piers. Two to four hours before the arrival of the center, coastal and low-lying escape routes flood. Small craft in unprotected anchorages break moorings.
Category3
111-130 MPH
Unanchored manufactured homes may be destroyed. Structural and some curtain wall damage occurs to small residences and utility buildings. Flooding destroys smaller structures near the coast. Larger structures are damaged by floating debris. Terrain that is continuously lower than five feet above sea level (ASL) may be flooded eight miles inland.
Category4
131-155 MPH
Extensive curtain wall failures with some complete roof structure failures on small residences may occur. Major erosion to beaches and damage to lower floors of structures near the shore occurs.
Terrain continuously lower than 10 feet above sea level (ASL) may be flooded requiring massive evacuation of residential areas as far as six miles inland.
Category5
155+ MPH
Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown over or away. Major damage to lower floors of all structures located less than 15 feet above sea level (ASL) and within 500 yards of the shoreline. Massive evacuation of residential areas on low ground within 5 to 10 miles of the shoreline may be required.
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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.
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