Two trends are converging in large wildland states like Montana — more frequent and severe wildfires and rapid home development in wildfire prone areas. A conference this week examined how homes burn and how to protect them.
Kelly Pohl is with Headwaters Economics, a non-profit research organization based in Bozeman. The group hosted the Building for Wildfire Summit in Big Sky this week along with the Big Sky Fire Department.
"We know that wildfires are becoming more intense, larger and lasting longer in our state, and the data backed this up. Wildfires have gotten bigger since the 1970s. The average acres burned per year is now about triple what it was a few decades ago," Pohl says.
According to the U.S. Forest Service, the wildfire season is also about three months longer due to a warming climate. In the last 20 years, the U.S. averaged $3.5 billion a year in insurance claims due to wildfire loss. It was $640 million a year during the 80s and 90s.
"The reason that we’re seeing more loss and destruction is because we are putting more and more homes in fire prone landscapes. The wildland-urban interface is the fastest growing land use type in the United States," Pohl says.
Pohl says one in three homes in the U.S. are in the wildland-urban interface. That’s where homes meet or intermingle with flammable vegetation — like a house built on the edge of a forest. In Montana, Pohl says more than half of the homes built here are in those kind of fire prone areas. The big sky state is ranked number one in the nation for the highest percentage of homes in areas with extreme risk to wildfires.
Jack Cohen, a retired fire behavior research scientist with the U.S. Forest Service, says wildfires are inevitable, but the destruction of homes and the loss of human lives is not. He’s spent his career studying why some homes burn while others remain unscathed.
Cohen shows a photo of Paradise, California where 85 people lost their lives and 14,000 residences were destroyed by wildfire last year.
"I was asked by numerous journalists, 'Can you explain the unusual pattern of destruction of the homes surrounded by unconsumed canopies?' I would respond, 'No, that’s the typical destruction,'" Cohen says.
Cohen’s research discovered embers from a wildfire — not the flames — are the main threat to homes. He found the characteristics of a home and its surroundings within 100 feet determine whether the structure will ignite.
"Wildland-urban fire disasters are a home ignition problem that can be solved by reducing home ignitability without necessarily controlling extreme wildfires. That’s a big deal," Cohen says.
Daniel Gorham is with the non-profit Insurance Institute for Business and Home Safety. His team does experiments to find better ways to build homes that can withstand fire.
Gorham plays a video from the research center where he works.
"What we did here was create a duplex structure, and half of it, we built with traditional building materials, and the other half of it, we built with wildfire resistant materials and techniques," Gorham says.
In the experiment, both units are showered with embers. The traditionally-built home has mulch landscaping, cedar shingle siding and open eaves. It takes less than a minute for the mulch to catch fire and the cedar shingle siding goes up in flames.
The unit right beside it — the one with rock landscaping, non-combustible siding, double-pane tempered glass windows, closed eaves and 1/8th inch metal mesh over the vents — is totally fine.
"[It] goes to show that all those individual components that we talk about [matter]. It’s not just the roof; it’s not just the eaves. It’s all the components together," Gorhman says.
The cost to build a wildfire resistant home is comparable to one built with traditional materials, according to the institute where he works. Gorhman says a fire-resistant roof is usually more expensive, but the siding is cheaper.
Maintenance is also key to protecting a home. That means removing pine needles and other debris from the roof, gutters and under the deck, storing firewood away from the home and keeping outdoor furniture, brooms and other flammable items inside. Even door mats can serve as kindling.
In the 30 feet radius around the building, researchers say homeowners should remove dead plant material and shrubs under trees, and prune branches overhanging the roof.
All of these measures don’t completely remove wildfire hazard, but they can mitigate it, especially if a whole community is working together.
At the summit, fire experts from Jackson Hole, Wyoming and Vail, Colorado shared how they evaluate each property in their communities on fire resilience. In Teton County homeowners are required to make changes to get up to code. In Vail, compliance is voluntary, but it's in the process of making landscape approval mandatory. The community is also developing a post-fire recovery plan.
Big Sky Deputy Fire Chief Dustin Tetrault says his department is working on education and outreach to encourage people to make their homes and businesses more fire-resistant. But in the future, he’d like Big Sky to go further and have a system where properties receive hazard ratings.
Resources for creating a fire-resistant home and community: