Many residents of fire-prone areas know to keep grass low and clear flammable materials like dry branches away from homes. But that likely isn’t enough to prepare for the wind-fueled firestorms or fire tornadoes that scatter fiery embers as much as a half-mile away.
Recent large fires whipped through California communities with such speed and force that they jumped what should serve as natural fire breaks. Forward progress of the Tubbs Fire wasn’t dissuaded by Highway 101 when a wall of flames leaped six lanes into a dense Santa Rosa neighborhood in 2017, and the Sacramento River couldn’t stop the Carr Fire from charging the city of Redding in July.
“Some of these fires are so intense that defensible space alone doesn’t solve the problem,” said Dan Turner, a retired Cal Fire chief who manages the San Luis Obispo County Fire Safe Council.
People can do more to minimize the potential for wildfire damage.
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Think about how fire ignites
Firefighters learn that there are three ways something becomes ignited: Convection (direct flame), radiation (when material bursts into flame from the heat of nearby fire) and convention (like flying embers).
Residents of the 2 million California homes considered high risk of wildfire damage need to think about all three.
That means removing all dead plants within 30 feet of your home or any structure, removing dry leaves and pine needles from the yard, roof and rain gutters and keeping tree branches 10 feet away from your chimney and other trees. Between 30 and 100 feet, cut grasses down to 4 inches and space out shrubs and trees.
If the flames can’t get within 100 feet, “radiant heat is not enough to ignite most houses,” Turner said.
Defensible space will protect against the convection and radiation, but it “doesn’t do anything to defend against embers,” which can be as big as your fist and can break a single-pane glass window, Turner said.
Prepare for flying embers
“We try to tell people that embers are a fire burglar trying to get into your house. If they can get in, they’ll ignite everything,” Turner said. “We’re not talking about two or three embers. We’re talking millions.”
“Literally look at the building. Where could an ember land and if it ignites, what is it going to burn?” Turner suggests. “Do leaves accumulate in a corner? Embers will accumulate there. It is a wood deck? Is it wood siding? If it’s just concrete, (the ember) will just sit there and cook (without igniting).”
Consider these measures when preparing your home:
- Leave absolutely nothing flammable within 5 feet of the house. No firewood stacks, no trash cans against the house, no mulch beds against the house. Nothing that embers can land in and ignite.
- Use nonflammable building materials. Think of the roof, walls, siding, deck and fences. Wood shake shingles are the worst. Build your roof or re-roof with materials like composition, metal or tile. On walls use stucco, fiber cement or fire-retardant treated wood.
- Cover chimney and vents. Use louvered vent covers so there is not a direct path for the ember to travel inside. Cover chimneys and stovepipe outlets with non-combustible metal screen.
- Look for openings and fill cracks. Check the weather stripping along garage doors, look for cracks or holes in the siding and make sure there aren’t open spaces under the house. Block everything so embers can’t get in.
Build a fire-safe community
All of this has to be a community effort to effectively minimize the potential for wildfire damage.
“If you did everything you can but your neighbor hasn’t done their work, your house is now at very high peril,” Turner said.
That’s why dozens of towns have assembled local Fire Safe Councils where diverse stakeholders from government planners to forest managers work together to maximize defenses, preparation and prevention.
Visit www.cafiresafecouncil.org to see where councils already exist and learn how to start one in your community.