Earth: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

Visual comparison of Hurricane Floyd with Hurricane Andrew while at similar positions and nearly identical intensities. Floyd was, however, 3–4 times larger and posed a much greater threat.

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

Determining size points

HSI Size Points
A total of 25 size points is possible.

Wind Radii	Size Point Range
35 kn	1–3
50 kn	1–4
65 kn	1–8
87 kn	1–10

See also

• Beaufort scale
• Fujita scale
• Outline of tropical cyclones
• Severe weather terminology (disambiguation)

External links

• Hebert, Chris, Bob Weinzapfel and Mark Chambers. “Hurricane Severity Index: A New Way of Estimating a Tropical Cyclone’s Destructive Potential”. 29th Conference on Hurricanes and Tropical Meteorology, 10–14 May 2010, Tucson, Arizona. American Meteorological Society. http://ams.confex.com/ams/29Hurricanes/techprogram/paper_168529.htm