Avalanches cut a deadly swath
Fifteen people have died over two weeks in the U.S. and Canada. Casualties at ski resorts underscore the danger.
Reporting from Denver — An unusual winter snowfall has triggered a series of avalanches in the high mountains that has killed nine people in the U.S. and six members of a snowmobiling group in British Columbia in the last two weeks.
Two other Canadians from the same small-town group are presumed dead. With increasingly treacherous conditions, Canadian avalanche forecasters warned skiers and snowmobilers that it was too risky to use the backcountry for the next several days.
In Wyoming, the Jackson Hole Mountain Resort closed its slopes Monday after a slide buried part of a restaurant, two days after an avalanche killed a skier.
"It's been snowing nonstop since Dec. 22," resort spokeswoman Lisa Watson said. "At this point, until this storm passes, we think this is an appropriate step."
This winter's unusual weather has created an instability in the layers of snow, resulting in avalanche conditions.
A fierce winter storm began dumping snow on the Rocky Mountains two weeks ago, which settled on top of an unusually thin layer of snow deposited during a comparatively dry November, making for a precarious snowpack.
In the recent slides, a slab of underlying snow is dislodged because of wind or pressure from new snow.
"It's like a brick on top of potato chips. And the potato chips can't hold the brick up," said Doug Abromeit, director of the U.S. Forest Service's National Avalanche Center in Ketchum, Idaho.
Ilya Storm, a forecaster in the Canadian Avalanche Center, said the light early snowfall and freezing temperatures led to snow crystals that didn't hold together, becoming a sugary, grainy powder beneath piles of more recent, thicker snow.
He said the storms lashing the region last week were the perfect catalyst.
"New snow and wind is the perfect recipe for building" an avalanche, he said.
Abromeit said the death toll in the backcountry was not unusual. It is the casualties at ski resorts, generally considered safe winter destinations, that illustrate how lethal the mountains have been this month.
Between 2005 and November 2008, four people died in avalanches on slopes at U.S. ski resorts. So far in December, three people have died on the slopes.
An avalanche at Utah's Snowbird resort killed a 20-year-old skier on Dec. 14. On Christmas Day, an experienced skier died in a slide in a forested area at Squaw Valley above Lake Tahoe.
- Avalanches Kill at Least 8 in Western Canada Jan 05, 1998
- Canada's Avalanche Experts Expect More Danger, Fatalities This Season Feb 14, 1998
- 3 German Skiers Killed in Avalanche Dec 17, 1996
