Vast areas of the Bay Area previously thought safe from wildfire are now at risk as climate change brings dramatic shifts in fire behavior — along with new technologies to help residents protect their homes.

Fire officials in the region say some of those new products may help, while others may do more harm than good.

Recent fires, including the 2017 Tubbs Fire that crossed six lanes of Highway 101 and razed a flatlands subdivision in Santa Rosa, the CZU wildfires in the Santa Cruz Mountains in 2020 that torched “fireproof” redwood forests, and last year’s Dixie Fire that crossed the Sierra Nevada have delivered a powerful and unsettling message: “We’re entering an era where if you live in the western United States you probably need to prepare your home for wildfire,” said Santa Clara County Fire Department Capt. Justin Stockman.

Extreme dryness and frequent high winds ushered in by climate change mean a blaze sparked in the flatlands has a much higher chance of tearing through neighborhoods, said Oakland Fire Department deputy chief Heather Mozdean. Last month, an ember from a Campbell house fire set afire a roof four houses away.

New products for homeowners range from relatively inexpensive gutter-mounted sprinkler kits to retardant-application systems costing tens of thousands of dollars. But these products are in many cases untested in the conditions particular to the Bay Area, and uncertainty about their effectiveness prevails.

Insurers have generally not embraced such technologies, but a fire-defense system might tip the odds of obtaining home coverage in a homeowner’s favor or produce a slight discount, said Tom Kelly, vice president of Orca Insurance in San Jose.

The Canada-made WASP sprinkler system is endorsed by many fire officials in heavily forested British Columbia, including Chief Gord Schreiner of Comox Fire Rescue. The quick-to-install, gutter-mounted technology is “a pretty simple concept but it’s very effective,” Schreiner said. But water is widely plentiful in the Comox Valley, from hydrants but also in lakes, ponds and streams, and Schreiner noted that British Columbia firefighters’ use of sprinklers depends on water supply.

In the Bay Area, alternative sources of water are more scarce, and fire officials worry about having to compete against homeowners. During the CZU fire, residents’ use of jury-rigged sprinkler setups meant firefighters sometimes lacked sufficient water pressure and by the time flames neared some properties, water tanks had long run out, Ben Lomond fire Chief Stacie Brownlee recalled with frustration. “It’s a huge issue,” Brownlee said.

During the 1991 firestorm in the Oakland hills, improvised sprinkler systems combined with systemic pump failures robbed firefighters of water, Mozdean said. The water system in the Oakland hills has been significantly upgraded since then, she said. “But speaking about residents in other areas, they may learn this lesson the hard way, too,” she said. “You can do something to try to save your house, but you have to be aware that we’re all in this together.”

Products applied to properties before fire comes may offer more promise, fire officials said. “Pre-treatment is a big deal. And it’s becoming a bigger deal,” said retired Menlo Park Fire District Chief Harold Schapelhouman.

Last month, Schapelhouman helped present a “wildfire preparedness fair” that featured Los Gatos company Komodo’s spray-on retardant, which can be applied to vegetation, decks, homes and outbuildings. The mix is water- and plant-based, biodegradable, and has just become one of only three such products to receive U.S. Forest Service approval, said Komodo CEO Shawn Sahbari. “We can claim a once-a-year application and you’ve got protection,” Sahbari said, adding that an extremely heavy rain could wash the product off.

To protect a three-bedroom house and its immediate surroundings would cost $200 to $300, he said. The product comes as a powdered concentrate or a ready-to-spray liquid, and in kits that include a backpack sprayer.

San Bruno fire Chief Ari Delay favors retardant gels sprayed onto structures when fire is approaching. Florida firm Barricade sells application kits suitable for a typical home for about $600. The gel is no panacea, as it offers relatively short-lived protection of six hours to three days, but, Delay said, “I am a very big believer.”

John DeLong, 72, who lives on 6 forested acres in the Santa Cruz Mountains, bought Barricade and said he would apply it if fire came close, even though its life span might prevent it from saving his house.

Far more expensive are automated systems that spray a water-and-retardant coating onto homes. Colorado-based waveGUARD sells a self-contained, automated system using heat detection of approaching flames and spraying of a microbe- and water-based retardant all over a structure, with batteries and a water tank insulating the equipment from blackouts or interruptions in water supply. Pricing starts at a whopping $80,000. Frontline Wildfire Defense, with an office in San Rafael, offers a biodegradable-foam-and-water sprinkler system that connects to plumbing, has a battery, and can be triggered remotely or on-site to coat a house. Prices start at around $25,000.

These costly products are good in concept, Stockman from the Santa Clara County Fire Department said, but “there are just so many unknowns as far as how they work.” Residents should talk to their local fire departments before installing or applying fire-protection technology, he advised.

Most important for urban, suburban and rural residents of areas at risk from wildfires, officials said, is clearing flammable materials from around homes, replacing combustible housing materials with fire-resistant products, having ember-resistant vents, making an evacuation plan, and getting out when the evacuation order comes.