All hurricanes are dangerous, but some more so than others. The way storm surge, wind, and other factors combine determines the hurricane’s destructive power. To make comparisons easier-and to make the predicted hazards of approaching hurricanes clearer to emergency forces-National Oceanic and Atmospheric Administration’s hurricane forecasters use a disaster-potential scale which assigns storms to five categories.
Category 1 is a minimum hurricane; category 5 is the worst case. The criteria for each category in the table shown below:
Category |
Central Pressure |
Maximum Winds |
Storm Surge |
Tropical Depression |
|
38 mph / 34 kts or less |
4-5 ft. |
Tropical Storm |
> 980 mb or 28.94 in |
39-73 mph or 34-63 kts |
4-5 ft. |
1 – Minimal |
< 980 mb or 28.94 in |
74-95 mph or 64-83 kts |
4-5 ft. |
2 – Moderate |
965-979 mb or 28.50-28.91 in |
96-110 mph or 65-96 kts |
6-8 ft. |
3 – Extensive |
945-964 mb or 27.91-28.47 in |
111-130 mph or 97-113 kts |
9-12ft. |
4 – Extreme |
920-944 mb or 27.17-27.88 in |
131-155 mph or 114-135 kts |
13-18 ft. |
>5 – Catastrophic |
< 920 mb or 27.17 in |
> 155 mph or 135 kts |
> 18 ft. |
* – The Saffir-Simpson Hurricane Scale is based on Windspeed alone, the pressures are only included as a general reference and may not always apply