Beginning this hurricane season, NOAA’s National Weather Service will use a revamped hurricane rating system that does away with storm surge effects of each category. The new scale, called the Saffir-Simpson Hurricane Wind Scale will use wind as its only determining factor.
Herbert Saffir and Robert Simpson developed the original Saffir-Simpson Hurricane Scale as a way to communicate the threat of hurricanes based on their power and released it to the public in 1973. In addition to wind, the scale used storm surge as a factor when determining a storm’s category rating.
Since then, scientists have realized that the amount of storm surge generated by a hurricane can vary greatly, well outside the wind guidelines of the original scale. According to NOAA, the storm intensity, size, pressure and the underwater topography near where a hurricane is going to make landfall make a large difference.
In announcing the new scale, NOAA pointed two recent storms to convey the problem with the old scale. Hurricane Ike made landfall along the Texas coast in 2008. While only a Category 2 storm, it produced storm surge of 15 to 20 feet. By contrast, Hurricane Charley in 2004 was a Category 4 storm that struck Florida but only generated a 6 to 7 foot storm surge.
Storm surge is extremely dangerous and flooding resulting from it and the tremendous rains generated by hurricanes claim more lives than wind. As such, storm surge forecasts will continue however they will be independent of the hurricane ratings. Beginning this year, when discussing surge, it will be expressed in height above ground level to help residents understand the potential for flooding in their area.
The revamped scale also was accompanied by new descriptions of wind impact while retaining the same wind speeds that were previously used.
