Dr. Timothy Reinhold, senior vice president of research and chief engineer at the Insurance Institute for Business & Home Safety (IBHS) and Dr. Mark Powell, an atmospheric scientist with NOAA's Atlantic Oceanographic and Meteorological Laboratories (AOML), have been awarded a U.S. patent for their integrated kinetic energy (IKE) scale.

The IKE scale is designed to better and more clearly convey predictions for each the two primary destructive elements of a hurricane: 1) the wind destructive potential (WDP) and 2) storm surge/wave destructive potential (SDP). The SDP is particularly important for large storms that may not necessarily have high wind destructive intensity ratings, such as Hurricane Katrina (2005) and Hurricane Ike (2008).

Tropical cyclone intensity in the Atlantic Basin is currently defined only by maximum sustained wind speed. Specifically, "the highest one-minute average wind at an elevation of 10 meters (33 feet) with an over-water, unobstructed exposure associated with that weather system at a particular point in time," is assigned a 1 to 5 damage potential rating using the Saffir-Simpson scale, explain Drs. Powell and Reinhold.

"People who lived in areas affected by Hurricane Katrina wondered how a storm that weaker than Hurricane Camille at landfall could have caused so much more destruction," said Dr. Reinhold. "It's because Katrina's large wind field maintained high surge/wave destructive potential ratings, despite relatively low wind destructive potential, and thus, a lower Saffir-Simpson scale ratings at landfall. In 2008, we again saw this disconnect and need to be more accurate predicting damage potential from both the surge and wind elements, as Hurricane Ike's Category 2 wind speeds were accompanied by a large storm surge that reached approximately twice the height that the Saffir-Simpson scale predicted. This was because of the storm's incredible integrated kinetic energy. Storm surge damage was terrible, and confirmed that we were on the right path with the new IKE rating system.

"The Saffir-Simpson scale serves a useful purpose for communicating relative risk to individuals and communities, but is a poor measure of the actual, destructive potential of a hurricane because it depends only on wind speed," said Dr. Reinhold. "A number of years ago, storm surge height were added to the Saffir-Simpson scale, but it recently was abandoned by the National Hurricane Center (NHC) because it is so poorly correlated with wind speed alone."

According to Powell, "IKE scales very well with the wind loading that causes damage to residential structures. The WDP was developed using loss data from land falling hurricanes, including Hurricane Andrew of 1992. IKE also relates well to the stress that the wind exerts on the ocean surface that helps form waves and storm surge. The SDP was developed using the wind fields of 23 hurricanes of various sizes and intensities. The new IKE scale offers a better differentiation between risk perception of wind and surge, which is an important goal for any new metric of hurricane destructive potential."

Based on the IKE of the wind field, ratings in the IKE scale assess destructive potential by a continuous scale that ranges from 0 to 5.99, comparable to the current Saffir-Simpson scale range, with which most people are familiar.

"The IKE scale provides a better early warning of the potential risks for surge and wind damage that can prove useful in personal planning for evacuations," explained Dr. Reinhold.

Powell's research team at AOML will be investigating these scale further this season using their H*Wind hurricane wind field analysis system. Research wind field products are available at www.hurricanewinds.noaa.gov, but these products and the IKE scales are not official National Weather Service products. Official hurricane forecast products are available from the (NHC).

"As the storm gets closer to landfall, actual predictions of wind speeds and surge levels in feet, that are based on local conditions and are issued by the NHC, will provide the best final guidance for preparations and evacuations. However, since more people die from storm surge than wind, and because long evacuation times are needed in many coastal communities, early warnings of surge potential are critically important - and that is where the IKE scale could make a huge and beneficial difference," Dr. Reinhold emphasized.

The basis for the patent issued June 28 (US 7,970,543 B2) was a research paper published in the Bulletin of the American Meteorological Society in 2007.

About IBHS

IBHS is an independent, nonprofit, scientific and educational organization supported by the property insurance industry. The organization works to reduce the social and economic effects of natural disasters and other risks to residential and commercial property by conducting research and advocating improved construction, maintenance and preparation practices.

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Joseph King
Media Relations Manager, IBHS