Catastrophe risk modeler AIR Worldwide has updated its Severe Thunderstorm Model for the United States, including significant enhancements to all three model components: hazard, engineering and financial.

According to a company statement, the improvements are based on a decade’s worth of new data and scientific research, including damage data collected and analyzed by AIR scientists and engineers following major outbreaks in 2008, 2011 and 2013; approximately $3 billion in insurance company claims; and additional analysis of billions of dollars of claims data from AIR’s sister company Xactware.

“The model update reflects a unique blend of statistical and physical modeling combined with the latest meteorological research to help overcome many of the limitations and reporting biases in the historical data. Such a model serves to provide companies with the high-resolution, detailed view of the risk needed to assess the impact of severe thunderstorm losses on their portfolios,” said Scott Stransky, manager and principal scientist at AIR Worldwide.

The model differentiates risks by subperil, such as tornadoes or hailstorms, and by building characteristics, according to Cagdas Kafali, assistant vice president and principal engineer at AIR Worldwide. The model accounts for primary building features (e.g., construction type, occupancy, number of stories and year built) as well as many secondary features, such as hail-resistance of the roof cover, Kafali said.

The AIR model not only captures the large outbreaks that produce insured losses in excess of $25 million but also the smaller events that may last only a day and produce much lower losses. In addition to the standard 10,000-year simulation, AIR said it will release 50,000- and 100,000-year stochastic simulations and a historical catalog containing several key recent events.

AIR has also released a Crop Hail Model for the United States—the industry’s first fully probabilistic model that captures the effects of hail on insured crops. The new model uses the 10,000-year stochastic catalog from AIR’s Severe Thunderstorm Model for the United States, in which hailstorms are a modeled peril.

The Crop Hail Model features crop-specific damage functions—for corn, soybeans, wheat, cotton, rice and barley—that account for the unique damage hail causes at various stages of each crop’s growth. The new model has been validated against loss estimates issued by the National Crop Insurance Services, data provided by crop insurers and published research, according to the statement.

The Severe Thunderstorm Model for the United States is available in Version 2.0 of the Touchstone and Version 16 of the CATRADER catastrophe risk management systems, while the Crop Hail Model for the United States is available in Version 16 of CATRADER.