Hurricane Severity Index: A More Efficient Way of Predicting a Tropical Cyclone's Destructive Potential

Hurricane Ike devastated the upper Texas coast as a Saffir-Simpson Category 2 hurricane in 2008. However, Ike produced a larger and more extensive storm surge and considerably more damage than did Category 3 Hurricane Alicia in 1983. In fact, Ike's storm surge on Galveston Island was nearly equal to the Category 4 Galveston hurricane of 1900 as well as the Category 4 hurricane of 1915. Clearly, the Saffir-Simpson hurricane scale is not adequate to measure a hurricane's true destructive potential.

Shortly after the devastating 2005 hurricane season, a new hurricane scale was developed that takes into account both a tropical cyclone's maximum sustained wind as well as the size of its wind field. This new scale is called the Hurricane Severity Index, or HSI. The HSI is a 50-point scale, with up to 25 points allotted for a tropical cyclone's intensity and up to 25 points allotted for the size of the wind field. The Hurricane Severity Index can be incorporated into a damage prediction model to better estimate a tropical cyclone's true destructive potential in terms of projected loss in dollars for the area impacted. In addition, the size component of the Hurricane Severity Index can be used to better estimate potential storm surge for a landfalling tropical cyclone.