The National Oceanic and Atmospheric Administration’s National Weather Service will use a new hurricane scale this season called the Saffir-Simpson Hurricane Wind Scale.
The scale keeps the same wind speed ranges as the original Saffir-Simpson Scale for each of the five hurricane categories, but no longer ties specific storm surge and flooding effects to each category.
Changes were made to the Saffir-Simpson Scale because storm surge values and associated flooding are dependent on a combination of the storm’s intensity, size, motion and barometric pressure, as well as the depth of the near-shore waters and local topographical features.
As a result, storm surge values can be significantly outside the ranges suggested in the original scale.
For example, Hurricane Ike in 2008 was a very large storm that made landfall on the upper Texas coast as a Category 2 hurricane with a peak storm surge of 15 to 20 feet. In contrast, Hurricane Charley struck Southwest Florida in 2004 as a Category 4 hurricane, but produced a peak storm surge of 6 to 7 feet. http://www.noaanews.noaa.gov/stories2010/20100217_hurricane.html