SAFFIR/SIMPSON HURRICANE SCALE RANGES
SCALE # CENTRAL PRESSURE WINDS SURGE DAMAGE
(CAT.) (MILLIBARS) (MPH) (FT.)
----------------------------------------------------------------------------
1 > 980 74 - 95 4 - 5 MINIMAL
2 965 - 979 96 -110 6 - 8 MODERATE
3 945 - 964 111 -130 9 -12 EXTENSIVE
4 920 - 944 131 -155 13 -18 EXTREME
5 < 920 > 155 > 18 CATASTROPHIC
FROM THIS WE OBTAIN TWO GENERAL FORMULAS FOR CALCULATING WIND SPEED FROM THE
MINIMUM CENTRAL PRESSURE OF A HURRICANE. HOWEVER, THERE IS AN ACTUAL FORMULA
USING THE MORE ACCURATE CYCLOSTROPHIC BALANCE, BUT THESE GENERAL ONES CAN BE
USED MORE EASILY, BECAUSE THEY REQUIRE KNOWING ONLY THE MIN CENTRAL PRESS.
1. WIND SPEED = 33 X {CUBE ROOT OF (1005-MIN. CENT. PRESS.)}
2. WIND SPEED = 35 X {CUBE ROOT OF (1000-MIN. CENT. PRESS.)}
*AVERAGING THE TWO CAN GIVE A RELATIVELY ACCURATE APPROXIMATION*
ETCS - Enhanced Tropical Cyclone Scale
SCALE #| CENT PRESS (MB) | WIND SPD | SURGE | DAMAGE | SS EQUIV.
-------|-----------------|------------|---------|--------------|-----------
1 | 1008 - 1010 | 15 - 39 | < 1 | None | Under 1
2 | 1004 - 1007 | 40 - 59 | 1 - 2 | Insignificant| Under 1
3 | 998 - 1003 | 60 - 74 | 2 - 3 | Minimal | Near 1
4 | 990 - 997 | 75 - 84 | 3 - 4 | Minor | Middle 1
5 | 980 - 989 | 85 - 94 | 4 - 5 | Light | High 1
6 | 965 - 979 | 95 - 109 | 6 - 8 | Moderate | Cat. 2
7 | 945 - 964 | 110 - 129 | 9 - 12 | Extensive | Cat. 3
8 | 920 - 944 | 130 - 154 | 13 - 18 | Extreme | Cat. 4
9 | 890 - 919 | 155 - 184 | 19 - 25 | Devestating | Cat. 5
10 | 855 - 889 | 185 - 219 | 26 - 35 | Catastrophic | High 5
