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.

Scenario – Hurricane WhatsHerName:

Hurricane WhatsHerName is a category 5 hurricane out in the Caribbean and moves into the Gulf of Mexico, hitting no land. The storm remains a category 5 hurricane for greater than 24 hours. The storm surge of WhatsHerName according to the Saffir-Simpson Scale is expected to be greater than 18ft at landfall, if it remains a category 5 hurricane.

WhatsHerName runs into some shear before coming to land in the Gulf of Mexico, dropping her winds and making her a cateogry 3 hurricane on the Saffir-Simpson scale. WhatsHerName is within 36 hours of land, storm warnings are posted. Since her winds have brought her down to a category 3 hurricane, the scale says that her storm surge should be 9-12ft, if you take the scale literally. However, the physics of water tells us that we should really be expecting a greater storm surge because the larger water base has been stirred into action, and water does not slow as quickly as winds. So, in reality, you should be expecting somewhere between category 4 (13-18ft) and category 5 ( greater than 18ft) storm surge with this category 3 storm.

The Saffir-Simpson scale works great when you are going up the scale. However, the flaw is when you come down the scale. It is my belief however that the scale is not at fault, but the understanding of the physics behind storm surge by the media and possibly our models which informs the public of what to expect. The models are getting better however, and we now have experimental storm surge data which will be available for the 2009 hurricane season.

With any luck though, our weather media will be able to do a great job of educating the public on what to expect this year, and hopefully prevent a large amount of the problems we see when the storms come our way this year.

In the mean time, make sure you are prepared for hurricane season this year. You can never prepare too early, only too late.

Category 1 is a minimum hurricane; category 5 is the worst case. The criteria for each category in the table shown below:

* – The Saffir-Simpson Hurricane Scale is based on Windspeed alone, the pressures are only included as a general reference and may not always apply