National Hurricane Conference and Storm Surge

With 21 days to go until the Northeast Pacific Hurricane season begins, and 38 days until the Atlantic Hurricane Season begins, it is time to make sure you are prepared.

April 6-10 was the National Hurricane Conference. This year it was held in Austin, Texas and covered a lot of great information including specifics about Ivan and it’s effects on the people of Texas. One of the major subjects of discussion was the Saffir-Simpson scale. Some say that the scale does not accurately portray the storm surge of a hurricane. I feel that the real problem is the lack of understanding of storms which are very strong (major) while out in the Gulf of Mexico, but weaken as they come closer to land. Continue reading

Saffir-Simpson Scale

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