Lessons learned from catastrophic and deadly wildfires that ravaged California in recent years could help residents and communities in and near forested areas limit damage from future fires, a first-of-its-kind study suggests.
And experts say the researchers’ conclusion that clearing flammable materials for five feet around houses — the area targeted as Zone 0 under a looming and controversial state-wide regulation — should also help residents in fire-risk zones understand the need for such measures.
UC Berkeley scientists studied five major wildfires the Wine Country’s 2017 Tubbs Fire, 2019 Kincade Fire and 2020 Glass Fire, plus the 2017 Thomas Fire in Southern California and the 2018 Camp Fire in Paradise that together burned some 27,000 structures and killed 109 people.Three key lessons for protecting homes from wildfire emerged, two of them applying to individual homeowners hardening houses against fire, and clearing nearby flammable materials like plants and fences and one requiring communitywide action.
“It isn’t just about you doing it,” said UC Berkeley fire scientist Michael Gollner, one of the study’s authors. “It’s really about a communitywide effort. You can do all the right things, and if your neighbors’ homes are not protected at all, that can create a really big risk.”
The researchers concluded that, especially in relatively dense neighborhoods, even if residents take diligent action in defense of their own houses, that may not matter much if their neighbors don’t.
In 2018 whole neighborhoods were destroyed by the Camp Fire near the Paradise Plaza off Clark Road in Paradise. (LiPo Ching/Bay Area News Group)
The closer together homes are, the more likely they are to transmit flames and embers to each other. In dense neighborhoods, clearing flammable materials from around a house and hardening it against fire typically “makes little difference on the survivability of a single home,” the study said.
However, the better individual homes are hardened with flame-resistant siding, roofs, windows and vents, and flammable surrounding items like vegetation, fences and sheds between houses are reduced, the less likely fire will spread from building to building, the study found.
“That’s where Zone 0 really becomes a critical component of this piece of the puzzle, not allowing the fire to travel too easily between homes,” said Steve Hawks, senior director for wildfire at the Insurance Institute for Business & Home Safety, a nonprofit funded by insurance companies.
Cutting that spread, Gollner said, helps avert what’s known as the “disaster sequence” when the number of houses on fire overwhelms firefighters.
“Every ember that doesn’t catch, every house that doesn’t burn, is a freed-up firefighter that can be putting out one that is,” Gollner said.
In 2019, fire and embers blow around a burnt utility truck during the Kincade fire in Healdsburg. Powerful winds were fanning wildfires in northern California in “potentially historic fire” conditions, authorities said. (Photo by JOSH EDELSON/AFP via Getty Images)
Gollner and his colleagues who also included researchers from other universities used computer models to reconstruct the five fires, and they dug deep into Cal Fire damage reports that included which structures burned, which survived, and in some cases, characteristics of buildings like siding type. Vegetation and structure mapping from aerial photos and satellite images were added to the mix.
When the researchers ran a scenario where all homes in a hypothetical wildfire had been hardened with nonflammable siding, fine mesh over vents, double-paned windows and fire-resistant roofing, a quarter of houses survived. When they added Zone 0 measures to all homes, the survival rate shot to 40%. Extending the clearing of flammables out to 30 feet boosted survival to 48%.
In the hills above Los Gatos, retired physicist Rick Parfitt, faced with cancellation of his home insurance policy over fire risk, cleared five feet around his home and poured concrete over much of that Zone 0 area. He replaced vent covers with tighter mesh and surrounded the base of his wood-sided home with an overlay of fire-resistant siding. For his efforts, which also included spending more than $7,000 to trim trees and cut down two redwoods and a fir, he was rewarded with a certificate from the Insurance Institute for Business & Home Safety that persuaded his insurer to maintain his coverage.
Rick Parfitt, a member of the Santa Cruz County FireSafe Council, stands on concrete steps that he made at his home in Los Gatos. Parfitt has done significant work clearing flammable materials from five feet around his home. (Shae Hammond/Bay Area News Group)
The researchers’ conclusion about the importance of Zone 0 clearing bolsters the foundation for the new regulation mandating the five-foot clearance in areas of very high fire hazard, experts said. The state Board of Forestry said Friday it is working on the regulation, which is supposed to be finalized by Jan. 1, but declined to say when it would go into effect and when it would be enforced.
Hawks has been tracking the forestry board’s Zone 0 work, and believes they may not hit the Jan. 1 target. Once the regulation is finalized, new homes in high-fire-danger areas will have to comply when built, and existing houses will have three years to meet Zone 0, Hawks said.
“There have been a number of people pushing back on the regulation,” said Hawks, who attended public workshops the forestry board held while developing the regulation. Some opponents object to changing the aesthetics of their property, while others worry about cost.. The study will likely help people understand the need to adopt Zone 0, Hawks said.
“It’s really important that the regulation be grounded in science, not anecdotal evidence that you see from photographs or aerial imagery from some of these fires,” Hawks said.
Gollner said grants and insurance discounts could help get reluctant or cash-strapped homeowners to take action on home hardening and property clearing.
Elizabeth Stage, whose Oakland hills home barely escaped the deadly 1991 firestorm, and whose work as president of the Oakland FireSafe Council involves persuading residents to adopt Zone 0 measures, said the study would be a helpful, persuasive tool. Tax credits could help lower-income homeowners, Stage said.
Keeping insurance is a major impetus for people to take action to protect their homes, along with awareness about their level of wildfire risk, said Parfitt, a board member of the Santa Clara County FireSafe Council. Parfitt urged homeowners to take advantage of grants, information and help with mitigation work available via local FireSafe Councils and FireWise community groups.
Gollner noted that devastating blazes in areas such as Coffey Park in Santa Rosa that burned in the Tubbs Fire show that flatland neighborhoods, including many in the Bay Area, are at risk during times of extreme heat, dryness and wind.
“If it happens, it’s going to be really bad,” Gollner said. “There are so many areas where we could make improvements.”
