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Back to Tropical Cyclones Winds Page | Back to Main FAQ Page

Subject: D1) How are Atlantic hurricanes ranked?

Contributed by Chris Landsea

The USA utilizes the Saffir-Simpson hurricane intensity scale (Simpson and Riehl 1981) for the Atlantic and Northeast Pacific basins to give an estimate of the potential flooding and damage to property given a hurricane's estimated intensity:

Saffir-Simpson Scale
Saffir-Simpson
Category
Maximum sustained wind speed Minimum central pressure Storm surge
mphm/s kts mb ft m
1 74-95 33-42 64-82 > 980 3-5 1.0-1.7
2 96-110 43-49 83-95 979-965 6-8 1.8-2.6
3 111-130 50-58 96-113 964-945 9-12 2.7-3.8
4 131-155 59-69 114-135 944-920 13-18 3.9-5.6
5 156+ 70+ 136+ < 920 19+ 5.7+

Note : Classification by central pressure was ended in the 1990s, and wind speed alone is now used. These estimates of the central pressure that accompany each category are for reference only.

Note : These surge values are for reference only. The actual storm surge experienced will depend on offshore bathymetery and onshore terrain and construction.

Damage
CategoryLevelDescriptionExample
1 MINIMAL Damage primarily to shrubbery, trees, foliage, and unanchored homes. No real damage to other structures. Some damage to poorly constructed signs. Low-lying coastal roads inundated, minor pier damage, some small craft in exposed anchorage torn from moorings. Hurricane Earl (1998)
2 MODERATE Considerable damage to shrubbery and tree foliage; some trees blown down. Major damage to exposed mobile homes. Extensive damage to poorly constructed signs. Some damage to roofing materials of buildings; some window and door damage. No major damage to buildings. Coast roads and low-lying escape routes inland cut by rising water 2 to 4 hours before arrival of hurricane center. Considerable damage to piers. Marinas flooded. Small craft in unprotected anchorages torn from moorings. Evacuation of some shoreline residences and low-lying areas required. Hurricane Georges (1998)
3 EXTENSIVE Foliage torn from trees; large trees blown down. Practically all poorly constructed signs blown down. Some damage to roofing materials of buildings; some wind and door damage. Some structural damage to small buildings. Mobile homes destroyed. Serious flooding at coast and many smaller structures near coast destroyed; larger structures near coast damaged by battering waves and floating debris. Low-lying escape routes inland cut by rising water 3 to 5 hours before hurricane center arrives. Flat terrain 5 feet of less above sea level flooded inland 8 miles or more. Evacuation of low- lying residences within several blocks of shoreline possibly required. Hurricane Fran (1996)
4 EXTREME Shrubs and trees blown down; all signs down. Extensive damage to roofing materials, windows and doors. Complete failures of roofs on many small residences. Complete destruction of mobile homes. Flat terrain 10 feet of less above sea level flooded inland as far as 6 miles. Major damage to lower floors of structures near shore due to flooding and battering by waves and floating debris. Low-lying escape routes inland cut by rising water 3 to 5 hours before hurricane center arrives. Major erosion of beaches. Massive evacuation of all residences within 500 yards of shore possibly required, and of single- story residences within 2 miles of shore. Hurricane Betsy (1965)
5 CATASTROPHIC Shrubs and trees blown down; considerable damage to roofs of buildings; all signs down. Very severe and extensive damage to windows and doors. Complete failure of roofs on many residences and industrial buildings. Extensive shattering of glass in windows and doors. Some complete building failures. Small buildings overturned or blown away. Complete destruction of mobile homes. Major damage to lower floors of all structures less than 15 feet above sea level within 500 yards of shore. Low-lying escape routes inland cut by rising water 3 to 5 hours before hurricane center arrives. Massive evacuation of residential areas on low ground within 5 to 10 miles of shore possibly required. Hurricane Camille (1969)

Note that tropical storms are not on this scale, but can produce extensive damage with rainfall-produced flooding. Note also that category 3, 4, and 5 hurricanes are collectively referred to as major (or intense) hurricanes. These major hurricanes cause over 83% of the damage in the USA even though they account for only 21% of tropical cyclone landfalls (Landsea 1993).

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