BERKELEY, CA – A new study from the University of California, Berkeley, provides compelling evidence that two key wildfire mitigation strategies home hardening and defensible space can drastically reduce the destructiveness of wildfires. The research, published in Nature Communications, shows that a combination of these measures can double a building’s chance of surviving a blaze, potentially cutting structure losses by as much as 50%.
The findings come as California communities grapple with the aftermath of devastating wildfires, including the recent fires in Los Angeles that caused billions in damages and displaced thousands.
Actionable Data for a Fiery Future
The study, led by Associate Professor Michael Gollner and postdoctoral scholar Maryam Zamanialaei, used a sophisticated approach to quantify the effectiveness of mitigation. The researchers combined state-of-the-art wildfire simulations with real-world data from five of California’s most destructive fires between 2017 and 2020. They analyzed data from more than 63,000 damaged or destroyed structures, incorporating information on building materials, vegetation, and the spacing between buildings.
Key findings include:
• Doubled Survival Rate: The study found that a combination of home hardening (using fire-resistant materials, covering vents) and defensible space (creating a buffer zone of clear vegetation) can double the number of structures that survive a wildfire.
• The Power of a 5-Foot Zone: The researchers found that simply clearing vegetation within a 5-foot perimeter of a home, a measure proposed in California’s “Zone Zero” regulations, could reduce structure losses by an impressive 17%.
• Separation is Key: The study also identified the distance between structures as the most influential factor in preventing fire spread, particularly in dense urban areas where fires can jump from building to building.
Gollner emphasized that the study provides powerful, data-driven justification for investing in these mitigation measures. “We can’t always change the spacing between structures or the exposure from flames and embers,” he said, “but even within those limitations, we still have the power to cut the destruction in half, if not more.”
A Community-Wide Effort
While the research highlights the significant impact of individual actions, Gollner noted that these strategies are most effective when adopted by an entire community. The study’s findings are intended to provide lawmakers and communities with the evidence needed to justify large-scale investment and cultivate the social and political will to implement these vital changes.
The research was supported by grants from the California Department of Forestry and Fire Protection (CAL FIRE), the Gordon and Betty Moore Foundation, and the National Science Foundation.