Damage Analysis of 2017-2018 California Wildfires Keys on Mitigation

New findings point to need for home improvements that resist embers, the cause of up to 90 percent of wildfire ignitions

Researchers identified key factors influencing the survivability of structures during a wildfire after surveying the devastation in Paradise, Calif. following the 2018 Camp Fire, the deadliest and most costly on record in the state, and data from six other California wildfire events in 2017-2018,

Researchers from the Insurance Institute for Business & Home Safety on Monday released a summary of the IBHS Post Event Investigation: California Wildfires of 2017 and 2018, which offers a new look at wildfire mitigation effectiveness.

Following the 2017-2018 wildfires, scientists matched Camp Fire field observations, along with those from other events, including the Tubbs, Woolsey and Carr Fires, to those seen during lab testing at the IBHS Research Center to further validate likely home ignition scenarios.

Key findings include:

• Mitigation is critical to give a home or commercial building a chance against wildfire but no guarantee of survivability.
• Mitigation efforts are most effective when building design, materials and surrounding defensible space are all addressed.
• Defensible space was an important characteristic of homes that survived the Camp Fire.
• Evidence of structure-to-structure fire spread was observed due to closely spaced homes.
• Firefighter intervention remains critical to saving structures, but that need can be reduced with effective mitigation.

While wildfires can ignite homes and businesses through direct flame contact, radiant heat exposure or wind-borne embers, the embers are the most serious threat and account for up to 90% of home ignitions, the report shows.

“Wildfires are influenced by available fuels, topography and weather conditions. Home and business owners can’t change topography or weather, but they can reduce available fuels on and around their structures through creating and maintaining a five-foot noncombustible zone and selecting noncombustible building components,” said Daniel Gorham, research engineer at IBHS.

Gorham noted that defensible space was an important characteristic of homes that survived the Camp Fire.

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