Catastrophe risk modeling company AIR Worldwide has released an updated wildfire risk model for the United States. The model gives a comprehensive view of the risk of wildfire to property within 13 western states, accounting for the variability of weather and its impact on fire behavior, the company said.
“AIR is committed to offering the most advanced tools for assessing potential insured losses from wildfire throughout the insurance and risk-transfer value chain,” said Dr. Jayanta Guin, executive vice president of AIR. “With the updates introduced in this model, AIR is building on our experience in modeling wildfires by introducing a fresh approach to estimating the hazard on both local and national levels, and accounting for the full range of vulnerabilities in residential, commercial and industrial lines of business.”
The new model incorporates a catalogue of fire clusters and historical data that features 17 events, including the 2017 Tubbs/Atlas and Thomas fires in California, the company said. Each cluster includes fires ignited within 150 miles of each other over a seven-day period. The company uses historical fire data to characterize wildfire behavior in difference ecological regions, or ecoprovinces, of North America.
“With residential and commercial development continuing to increase in areas prone to wildfire risk, the model explicitly accounts for this increased penetration into the WUI (wildland-urban interface),” said Tammy Viggato, senior scientist at AIR. “Approximately one third of the US population currently lives in the WUI in the United States, where most wildfire-related losses occur, and this figure continues to grow rapidly. To address the increasing risk, the model realistically captures fire behavior as it moves from rural areas to the suburbs, and – under extreme conditions – into more urban areas.”
The new model simulates how fires spread based on wind speed and direction, availability of fuel, terrain, and the likelihood of suppression, AIR said. It also accounts for the different ways fires spread. The model calculates flame length at each time step, which correlates with the intensity of the fire and can be used to estimate the severity of its damage.