The Saffir-Simpson Scale


Since some hurricanes are more dangerous than others, the way in which the storm surge, wind and other factors combine will determine the hurricane's destructive power. For comparison and clarification of the potential hazards of an approaching hurricane, NOAA hurricane forecasters use a disaster-potential scale which assigns storms to one of five categories. Category 1 is a minimal hurricane; category 5 is the worst case. The criteria for each category are shown below.


Category 1:

Wind speed 74 to 95 mph or storm surge 4 to 5 feet above normal. No real damage to building structures. Damage primarily to unanchored mobile homes, shrubbery and trees. Also, some coastal road flooding and minor pier damage.


Category 2:

Wind speed 96 to 110 mph or storm surge 6 to 8 feet above normal. Some roofing material, door and window damage to buildings. Considerable damage to vegetation, mobile homes and piers. Coastal and low-lying escape routes flood 2 to 4 hours before arrival of the center. Small craft in unprotected anchorages break moorings.


Category 3:

Wind speed 111 to 130 mph or storm surge 9 to 12 feet above normal. Some structural damage to small residences and utility buildings with a minor amount of curtain wall failures. Mobile homes are destroyed. Flooding near the coast destroys smaller structures, with larger structures damaged by floating debris. Terrain continuously lower than 5 feet above sea level may be flooded inland as far as 6 miles.


Category 4:

Wind speed 131 to 155 mph or storm surge 13 to 18 feet above normal. More extensive curtain wall failures with some complete roof structure failure on small residences. Major erosion of beach areas. Major damage to lower floors of structures near the shore. Terrain continuously lower than 10 feet above seal level may be flooding, requiring massive evacuation of residential areas inland as far as 6 miles.


Category 5:

Wind speed greater than 155 mph or storm surge greater than 18 feet above normal. 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 levels 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.


CATEGORYCENTRAL PRESSURE
(Millibars)
(Inches)
WINDS (MPH) SURGE (FT) DAMAGESTORM
1
980 +
28.94 +
74-95 4-5 MINIMAL AGNES 1972
2
965-979
28.50-28.91
96-110 6-8MODERATE KATE 1965
3
945-964
27.91-28.47
111-130 9-12EXTENSIVE ELENA 1985
4
920-944
27.17-27.88
131-155 13-18 EXTREMEANDREW 1992
5
920
< 27.17
155+ 18+ CATASTROPHICLABOR DAY 1935


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