The Hurricane Severity Index (or HSI) measures the strength and destructive capability of a storm based on its size and wind intensity. The HSI attempts to demonstrate that two hurricanes of similar intensity may have different destructive capability due to variances in size, and furthermore that a less intense, but very large hurricane, may in fact be more destructive than a smaller, more intense hurricane. It is very similar to the Chicago Mercantile Exchange Hurricane Index, which also factors both size and intensity of a hurricane. HSI was developed by a private company program in competition with the National Weather Service's accumulated cyclone energy index. HSI was developed by ImpactWeather (now StormGeo) meteorologists as a proprietary method of hurricane severity classification. HSI misclassifies hurricanes in some cases because it does not account for rainfall. HSI is based on a lookup table rather than an equation. It does not take into account the translational speed of the storm.

Components of the index

The Hurricane Severity Index is a 50-point scale, with wind intensity and size contributing equally.

Determining size points