Avalanches weren’t – and aren’t – only a backcountry threat

 

In the handful of times I’ve visited Missoula, Montana, the grassy slopes of neighboring L- and M-emblazoned Mounts Jumbo and Sentinel have never looked any more threatening to me than the hogbacked foothills that yaw out of the ground west of Boulder, Colorado, my hometown. Velvety, yes. Curved like a set of relaxed shoulders, yes. Welcomingly draped in the low-angled sun of late afternoon, yes. Avalanche death zone? Not so much.

But on Feb. 28, an unusually intense blizzard snapped a wet quilt of deep snow over the valley, rumpling it into drifts and slabs with gusts up to 50 mph. Atop Jumbo and Sentinel, as well as the surrounding mountains, a weak crust of ice that unseasonably warm weather had glazed over the existing snowpack earlier in the week strained beneath the weight. When a group of snowboarders started down Jumbo closed since November to protect a wintering elk herd – around 4 p.m., that strain released spectacularly. A large slab avalanche ran from near the mountain’s peak almost 1,300 vertical feet into a neighborhood on the valley floor, obliterating a two-story house, damaging several other homes and vehicles, and worst of all, burying three people. Over 100 first responders, search and rescue personnel, neighbors and volunteers converged on the area with shovels and probes to find and dig them out. All were recovered alive; one ultimately died from her injuries.

The Jumbo avalanche path of Feb. 2014, marked in red, in Missoula, Montana. Courtesy City of Missoula.

It was, according to most accounts, a freak accident. No one can remember a big slide coming down that path in the 60 to 80 years homes have been at its base, says Assistant Director of Missoula Development Services Don Verrue. In fact, any in-town avalanche fatality is kind of a freak thing these days; most folks unlucky enough to get caught (and it’s been a bad winter, with 22 killed to date) are far in the backcountry, chasing turns on fresh powder. But it wasn’t always that way: Avalanches used to exact their biggest toll on unlucky travelers, miners and mountain communities, not on farflung skiers.


The worst such event in U.S. history occurred March 1, 1910. During an epic snowstorm, blizzard-drifted snow and avalanches stranded two trains in the small Cascades mountain town of Wellington, Washington, about 85 miles east of Seattle. Then, the weather turned suddenly to rain and warm wind, sending a slide down in the middle of the night that knocked both trains – and the 50 passengers and 75 railroad employees sleeping on board – into a deep ravine. Ninety-six people died. Just three days later, Canada experienced its own superlative avalanche, when a slide in British Columbia’s Selkirk Mountains killed 58 men clearing avalanched snow from a railroad line below Rogers Pass.

Train wreckage left by the 1910 slide in Wellington, Washington. Courtesy Library of Congress.

Colorado has also had its share of terrible accidents. The worst of these occurred at the Liberty Bell Mine above Telluride in 1902, when multiple slides claimed a dozen miners, and then the same number of would-be rescuers. According to a review of recorded avalanche fatalities in the state, assembled by Dale Atkins of the Colorado Avalanche Information Center, 92 percent of the 442 people killed between 1859 and 1920 were those simply working and living in the mountains, the vast majority of them miners brought by the silver mining boom. But as mining waned and the ski industry and outdoor recreation came into their own as major economic drivers in the state, a new trend emerged. Between 1950 and 2006, 81 percent of the 210 people killed in avalanches were playing in the snow – climbing, skiing, snowshoeing and snowmobiling.

That’s still fewer than half the deaths of the mining years, despite massive increases in Colorado’s population and the number of people traveling through the mountains. Part of what’s changed, in Colorado and elsewhere, is that we’ve gotten better at predicting and mitigating avalanche danger, explains geotechnical engineer Chris Wilbur, who works on avalanche mitigation and land-use planning projects around the West. Instead of simply crossing fingers and whispering prayers when we drive over 10,662-foot Vail Pass, for example, we can trust in weather forecasters and snowpack monitors, the state highway department, which closes roads beneath slide paths when the danger is high, and the trusty folks who lob explosives onto overloaded slopes to release slides while those roads are closed, so that they can be cleared away without loss of life or limb.

There’s also now protective infrastructure in some of the most dangerous places – like tunnels at those northwestern carnage sites I mentioned earlier – that helps deflect or bypass snow. Wilbur is currently working with Washington state to replace an inadequate snowshed on Snoqualmie Pass – meant to channel avalanches safely over the interstate – with a six-lane bridge over the slide path. Officials expect the $71 million project to reduce road closures 10-fold, and thus reduce the massive economic disturbances associated with blocked freight and traffic, Wilbur says.

Several mountain communities, including Aspen and Pitkin County, San Juan County, Ophir, Vail and others in Colorado starting in the 1970s, Sun Valley and Ketcham, Idaho, and Anchorage and Juneau, Alaska, have also adopted avalanche zoning and land-use codes that prohibit structures or require building designs that can withstand avalanche forces in known active slide paths, depending on how frequent they are, Wilbur says. The codes are adapted from Swiss policies, with some key tweaks to accommodate Americans’ sense that private property rights are sacred above nearly everything else – for example, being less strict about how frequent slides need to be to prohibit building. The communities in Utah’s highly avalanche-prone Little Cottonwood Canyon, meanwhile, have “interlodge” warnings, requiring residents to shelter in avalanche-fortified buildings – for minutes, hours or even days – until officials declare it safe again after bombing surrounding slopes to set off slides.

Juneau may have the worst urban avalanche potential in the country, with 62 houses, a hotel and a harbor within an active slide area. “There’s the possibility of the most catastrophic avalanche disaster in American history if all things go the wrong way,” says city avalanche forecaster Tom Mattice. There’ve been many close calls – including a 1962 avalanche that damaged two dozen homes, tearing off roofs, buckling walls, breaking chimneys and windows – but as of yet no fatalities. The city now has codes in place to prevent new building in the worst spots. But since much of the area is already built out, its best option to head off disaster may simply be to buy out many of the area’s homeowners with the aid of federal hazard mitigation and disaster prevention grants – a prospect it’s now studying.

In the meantime, Juneau trains its fire department and other emergency responders in urban avalanche rescue, which involves everything from dealing with hazardous materials and dangerously unstable building debris to live electrical wires and spewing gas lines, not to mention all the usual probe-’n’-beacon stuff mountain enthusiasts are so familiar with.

Missoula’s Don Verrue says the city will emulate that part of Juneau’s approach to prepare for any future avalanches within its borders – which local forecasters say is a possibility, however remote. There’s just not usually enough snow to justify land-use code changes, Verrue explains.

Even so, the Missoula slide is a good reminder that we live in an uncertain, constantly shifting world – one where the right combination of weather and topography can quickly obliterate the artificial lines we’ve drawn between our orderly communities and chaotic forces of nature.

Sarah Gilman is High Country News’ associate editor. She tweets @Sarah_Gilman