“I hate to be the bearer of bad news, but that is the reality,” said Steve Karkanen of the West Central Montana Avalanche Center in Missoula. Unless an unseasonable heat wave melds the snowpack together, or avalanches scour the slopes and snow begins again from scratch, “then it's going to be a pretty tricky year,” Karkanen said. “That weak layer is pretty well insulated down there, so it's not going away anytime soon.”
Monday, Karkanen issued an avalanche warning for the mountains around Missoula, including the Bitterroot Range, Rattlesnake Mountains, southern Mission Mountains and the Swan Range near Seeley Lake.
His warning came three days after the Canadian Avalanche Centre issued warnings for parts of British Columbia, and one day after 11 snowmobilers were buried southwest of Fernie, B.C., in the Canadian Flathead River Valley, about 20 miles north of the Montana border.
The friends - all young men from Sparwood, B.C. - had split into two groups, authorities said, and seven sledders were buried when snow slid down the mountainside at about 2 p.m. Sunday. The remaining four snowmobilers rode in to rescue their friends, but were hit by a second slide.
Two men managed to dig themselves out, and then located a third. Recovery teams had found the bodies of seven snowmobilers Monday and an eighth was believed dead.
Generally, backcountry safety experts advise against putting more than one person at a time onto a dangerous slope, so as to avoid multiple burials.
“But it's becoming a kind of a common theme,” Karkanen said. “Unfortunately, when you put more than one person on a slope at a time, it puts way more lives at risk. And sometimes it means there's no one left to make the rescue.”
Although he had not been to the Canadian site, Karkanen suspected the avalanche may have been caused by a weak and icy layer buried almost at ground level, which is “a pretty widespread condition throughout the West this year.”
Back in late November and early December, a warmup and light rain soaked the early snowpack, which then re-froze into an icy sheet. Atop that sheet fell weeks of extremely cold and dry snow, so light and airy that it did not consolidate well.
High winds churned the top several inches into a layer of wind-packed spindrift, deposited on leeward slopes and in gullies and other “powder traps.”
“And then, this weekend, we saw really high temperatures on top of all that light snow,” Karkanen said. A heavy, dense snow weighed down the weak fluff beneath, melding it into a slab, pressing it against the buried ice layer and creating what Karkanen called “darn scary conditions.”
In some places, the added weight proved too much, and slabs cut loose on the icy sheet beneath. In other places, the hillsides held until people added their weight to the pack.
“This system came in at much warmer mountain temperatures than we've seen in about three weeks,” Karkanen said, “giving us avalanche conditions that have not been seen here in years.”
The weak and airy snow cannot support the heavy load above, he said, and “has brought most slopes to the brink.”
“New snow and more high winds will keep the snowpack at its tipping point,” agreed Mark Staples, who reports for the Gallatin National Forest Avalanche Center. “Whether it takes a human or one additional snowflake to tip the balance, avalanches will occur.”
In addition to the eight Canadians killed in Sunday's slide, two more snowmobilers died in a Colorado avalanche over the weekend. Also in Colorado, a natural slide closed U.S. Highway 6 over Loveland Pass.
“In addition to avoiding avalanche terrain, I wouldn't even go near it,” Staples said.
In his area of southwest Montana, an avalanche warning persists in the southern Gallatin and Madison ranges, the Lionhead area near West Yellowstone, the mountains around Cooke City and the Washburn Range, in northern Yellowstone National Park.
The most dangerous spots, as elsewhere, are wind-loaded slopes with a heavy pack perched atop that buried ice layer.
Last January, two men died north of Whitefish when a snow slab slid on a similar ice layer. That sheet had been laid down more than a month before, when early-season snow melted and then froze hard.
Later snowfalls did not adhere to that hard sheet, creating a sort of horizontal fault line that slipped loose when 19-year-old skier Anthony Kollmann added his weight to the pack.
This year's snowpack is providing “clear warning signs,” Staples said, and avalanche analysts themselves triggered a 1,000-foot-wide slide near Cooke City this weekend. Skiers kicked off another large avalanche near West Yellowstone, and other backcountry users reported a cracking and collapsing pack, and not just on steep slopes.
Karkanen, in fact, is urging caution even on the relatively safe foothills around Missoula. In 1993, a young man died in an avalanche on Mount Jumbo, within sight of East Missoula. Those kinds of areas are “worth paying attention to during unusual winter conditions,” he said, “and we have unusual conditions this year.”
Karkanen suspects “it's going to be a nasty winter in terms of avalanches,” because “we rarely have a buried ice layer like this followed by such cold temperatures. Now, that layer is insulated down there, and it's going to be there for a long time.”
Recent snowfall - and a prediction of more to come - is welcome, he said, and will provide much-needed moisture come spring.
“But it is coming with a price, and that price is dangerous avalanche conditions.”
Karkanen advises people to find fresh tracks in the flats for now, and to play in places not prone to avalanches.
After all, he said, it is not a good thing to die, even when doing what you love - instead, it's better to live to do it again and again, “and right now, that means waiting for a safer day.”
Reporter Michael Jamison can be reached at 1-800-366-7186 or at mjamison@missoulian.com.
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