When the Eaton Fire burned in Los Angeles County in early January, 75% of the structures in the fire perimeter had a low to moderate wildfire hazard, but they carried a high to very high conflagration hazard. Eighty-four percent of structures affected or destroyed by the blaze carried this very high conflagration categorization, a new analysis shows.
Cotality conducted a retrospective analysis of the devastating Palisades and Eaton fires using two of its wildfire products and shared the results in a recent wildfire report. That analysis found that properties assessed as low or moderate wildfire hazard may still face high or very high conflagration risk, especially in wildfire-prone areas.
Wildfire-induced conflagration occurs when wildfire transitions from a natural vegetation environment into a built environment, allowing fire to spread between structures. Cotality determines conflagration hazard based on how the structures themselves can contribute to the potential for loss once a wildfire meets the built environment. That assement includes structure density, structure characteristics, weather and climate.
It differs from wildfire risk, which looks at the hazard on or surrounding a location by considering factors like risk on the property, distance to high-hazard fuels, open wildland, as well as wind and drought.
While this transition between environments may seem subtle, it fundamentally alters the fire’s behavior, impacting how it spreads, where it travels and the scale of its potential destruction, Cotality, formerly CoreLogic, said in its report.
“This is important for carriers, as there is heightened risk tied to certain structures because of the factors that drive conflagration,” Jamie Knippen, the data and technology company’s wildfire product manager, said in an interview. “And that’s what we saw in [the] Palisades and Eaton [fires], and why so many structures were ultimately destroyed.”
The structures were densely packed—some standing less than 10 feet apart from each other—and many were older homes that weren’t as mitigated as they potentially could have been because they weren’t required to adhere to new California building codes, Knippen explained.