Scales

Saffir-Simpson Scale | Fujita Scale | Sea States

Saffir-Simpson Scale

The Saffir-Simpson scale measures the intensity of hurricanes.

Category Wind Speed (mph) Wind Speed (kts) Pressure (mb) Pressure (in) Storm Surge (ft)
Tropical Depression 23-39 20-34 . . .
Tropical Storm 40-74 35-64 . . .
1 75-95 64-83 980 28.94 4-5
2 96-110 84-96 965-979 28.50-28.91 6-8
3 111-130 97-113 945-964 27.91-28.47 9-12
4 131-155 114-135 920-944 27.17-27.88 13-18
5 155+ 135+ below 920 below 27.17 18+
Note: There is no Category 6 or higher on the Saffir-Simpson Scale.

Fujita Scale

The Fujita Scale is primarily a measurement of wind damage. It is used to describe tornadoes by the severity of the damage that they cause, and can be used to describe the wind damage created by a hurricane. The scale was developed by Dr. Ted Fujita.

Classification Wind Speed (mph) Damage
F0 40-72 Minor
F1 73-112 Moderate
F2 113-157 Significant
F3 158-206 Severe
F4 207-260 Devastating
F5 261-318 Incredible

Sea States

Sea State Wave Height (ft) Wind Speed (kts) Description
1 0-1 4-6 Smooth sea, no foam
2 1-2 7-10 Slight sea, small wavelets, no foam
3 2-4 11-16 Moderate sea, large wavelets, crests begin to break
4 4-8 17-21 Rough sea, moderate waves, many white caps
5 8-13 22-27 Very rough, seas heap up, spindrift and foam streaks
6 13-20 28-47 High sea, seas begin to roll, dense streaks of foam and spray
7 20-30 48-55 Very high sea, very high waves with overhanging crests, visibility reduced
8 30-45 56-63 Mountainous sea, very high, rolling, breaking waves, sea covered with foam, very poor visibility
Note: The wind speeds required to produce Sea State 8 are below minimal hurricane speeds. Higher winds for a sustained period, over a sufficient stretch of ocean, will produce higher seas.
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