A year ago this month, Missoula city councilors voiced concerns about a house proposed to be built on the same site where an avalanche destroyed the previous home and injured four people, one of them fatally.
What they learned, however, was that the city has no regulations regarding avalanche zones.
“Why are we building in avalanche zones? Even asking seems crazy. What are our options?” Julie Armstrong asked at the time.
Without avalanche zone regulations, private property owners have the right to build wherever they choose. The homeowner on this site told the City Council he was implementing various tactics to steel the house against an avalanche — like shear walls and anchor bolts — on his own to protect the property.
The homeowner declined to comment Thursday, after another snow slide close to the same location, on the potential future avalanche risk.
Chris Wilbur is a geotechnical engineer with Mears and Wilbur, a Colorado-based company that does engineering and land use planning work for snow avalanches. Wilbur said he visited Missoula after the 2014 avalanche to find out for himself what the hazards are and whether they could be mitigated.
“The typical approach is rather than mitigate, to get the hazards mapped and apply zoning that requires protection to be built into Missoula homes themselves,” Wilbur said. “That’s the most efficient and cost-effective way to deal with it.”
Those maps typically show high-, medium- and low-hazard zones, with related building restrictions. Wilbur said Sun Valley and Ketchum in Idaho, and Vail and Aspen in Colorado all have avalanche ordinances, but those communities have higher exposure risks than Missoula.
“I could tell by visiting the Rattlesnake area that it would make it uneconomical to build there if they implemented typical avalanche ordinances, because the cost of construction would go up so much,” Wilbur said.
He added that Europe has protective structural defenses in place, but those are quite expensive. In Washington state, Snoqualmie Pass avalanche mitigation structures cost about $75 million, and he estimated work protecting the homes around Mount Jumbo would top $10 million.
Instead, another typical lower-cost tactic often used on a short-term basis is to create hazard maps to lay the groundwork for implementing voluntary or mandatory evacuations.
Missoula Fire Chief Jeff Brandt said while the department doesn't have formal avalanche hazard maps, they use forecasts and maps from other organizations, and they monitor areas around the city where they know of potential hazards. But mostly, they rely on “boots on the ground” personal information; on Thursday, the City of Missoula’s contracted avalanche danger assessment experts visited Mount Jumbo to check out the conditions.
He added that unlike wildfires on public lands, “there’s no way I can tell you how to protect yourself with a snow situation above your home.” But he does refer people to missoulaavalanche.org.
The Missoula County Office of Emergency Management issued an urban avalanche warning via cellphones and land lines to residents living at the base of Mount Jumbo on both the Rattlesnake and East Missoula sides, alerting them to possible danger. Wilbur said that’s what many communities do with elevated avalanche risks.
Blake Meyers, a senior firefighter, added that they also do annual training for search and rescues in case an avalanche does occur.
“I think people in town are really aware of avalanches,” Meyers said at a press conference Thursday afternoon. “We have scenarios we train for every year.”
According to a handful of insurance agents contacted by the Missoulian, homeowners can’t purchase actual avalanche insurance. However, Tom Monaghan with Summit insurance said two kinds of insurance policies are common: those that tell homeowners what specifically is covered, and those that have blanket coverage but list exceptions.
“Most are the latter, with something like earthquakes or floods,” Monaghan said. “Avalanches aren’t a typical exclusion, but I could also see where potentially an insurance company could see it as being similar to a mudslide, which is a specific exclusion. It’s important for every client to check with their own carrier.”