CARVILL HURRICANE INDEX™

Carvill’s ReAdvisory team recently created the Carvill Hurricane Index (CHI), which determines a numerical measure of the potential for damage from a hurricane.  The commonly used Saffir-Simpson Hurricane Scale (SSHS) classifies hurricanes in categories from 1 to 5; however there are a number of features which make the scale less than optimal for use by the insurance community, and the public at large. 

For example, meteorologists have had to quantify SSHS categories as either ‘strong’ or ‘weak’ in order to make a proper distinction of a storm.  As a case in point, Katrina was described as a weak category 4 storm at the time of its landfall but this did not provide a real estimate to the actual physical impact.

The CHI incorporates additional factors about the hurricane, such as sustained wind speed and the radius of hurricane force winds, and is a continuous measurement, rather than a discrete scale, starting from zero and has no maximum value.  For example, Hurricane Wilma in 2005 was at one point in its life the strongest storm on record.  However, the CHI highlights that, at its strongest, Hurricane Katrina had more potential for damage than Wilma, despite its lower wind speed, since Katrina was a far wider storm.  The Saffir-Simpson scale would be unable to make this distinction clear.

For further information on the CHI go to ReAdvisory Reports on the following:

• Carvill Hurricane Index white paper
• CHI Questions and Answers
• CHI Scope and Definitions
• Historical CHI Values Based on NHC Data - 1998 to 2006