Hurricane Severity Index
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.
Components of the index
The Hurricane Severity Index is a 50-point scale, with wind intensity and size contributing equally.
Determining size points
Wind Radii | Size Point Range |
---|---|
35 kn | 1–3 |
50 kn | 1–4 |
65 kn | 1–8 |
87 kn | 1–10 |