Avalanches Kill at Least 12 People in Four Days
Heavy Snowfall Brings People Out to Danger

Avalanche off the Nuptse Ridge to the Western Cwm south of Everest.
(photo: Todd Burleson)
Tuesday, January 6, 1998

At least 12 people have died over the last four days due to an unprecedented concentration of avalanches in a region of North America that includes British Columbia, Washington State, Idaho and Montana. The avalanches themselves are nothing out of the ordinary, but the high death toll is.

After a severely dry early winter, the heavy snows that have fallen since the solstice on December 21 have drawn pent up winter sports enthusiasts out in highly dangerous conditions. It's ironic that at least two of those killed, a snowmobiler and a backcountry trekker, were avalanche experts who taught avalanche safety.

A 15-foot slab on Mount Rainier
(photo: Gary Brill)
"Primarily, you get avalanches anytime you have problems in the snowpack — weak structure, bad layers or too much snow," Gary Brill, an avalanche instructor and long time backcountry skier from the Pacific Northwest, told The Mountain Zone. Weak layers in the snowpack can be a result of changing weather, for example, warming and re-freezing. When snow "recrystallizes," it gets weaker.

Had the heavy snow currently falling in the Northwest come a few weeks earlier, Brill said, there may well have been catastrophe. But, at that time, warm temperatures led to rain instead of the more precarious snowfall. This rain then covered an already weak snowpack. "Initially it destabilized it, but people weren't out," he said.

"The only reason we didn't get deaths early on is because nobody was out there to die," Brill said.

In these areas of Washington State and into the northern parts of Oregon, warmer snow, which is denser, continues to fall on top of drier, less dense snow. This, though, is not out of the ordinary for the Pacific Northwest. "We've had a late start for the snow year," Kenny Kramer, a meteorologist with the Northwest Weather and Avalanche Center said. In a "normal" winter, he said, there may be 30 to 40 high danger avalanche warnings.

In British Columbia, where the majority of deaths occurred, cold, dry conditions can mean a weak snowpack all the way to the ground, said Alan Davis, managing director of the Canadian Avalanche Center.

The deadly slides of January 2-3, he said, are a culmination of events since November. First, was the "snow starvation" in the early winter, followed by "three significant events: heavy snowfall, severe warming, and a cold northerly outbreak (heavy snows and heavy winds which also move the snow)," Davis said.

This layering of snow with different characteristics causes snowpack to be very sensitive — "it's the cycles," Davis said, "the natural ebb and flow of good weather." The recent heavy volumes of snow are sitting on a shallow and weak snowpack.

The Northern Columbia area of B.C., which includes the Kokanee Glacier Park, where six skiers died Friday, continues to be an area of high avalanche danger and heavy continuing snowfall. A Kokanee area local told The Mountain Zone that one Kokanee Glacier slide over the weekend was "a monster, a kilometer wide and 50 feet deep at the top." The people killed were below the avalanche and were overcome by it. (Rescue attempts were hampered by heavy snow and the sixth body had yet to be recovered by Tuesday afternoon.)

Avalanches can be triggered a number of ways, with the obvious being people on top of the snow slide. But, people can also trigger a slide from a quarter mile away, Brill said. Weak layers of snow propagate energy that can travel far away, so be aware that, even if you are on a flat surface, an avalanche can be triggered above. There are also natural avalanches that, when fatal, are simply cases of being in the wrong place at the wrong time.

While winter enthusiasts have waited a long time for the snows that continue to fall and pent-up excitement can lead to spur-of-the-moment adventures, it is important during heavy avalanche times to keep to mainstream winter activity areas, where snow is regularly compacted by use. Backcountry skiers, climbers, snowmobilers and snowshoers should use extreme caution and obtain up-to-date information, through avalanche hotlines and avalanche center web sites, before venturing out.

"In the backcountry you don't have that compaction so there are several days of snow that can be released," Brill said.

The only other advice given by all the experts to keep safe is to have the knowledge and experience of winter avalanche trends in the area to be visited. Otherwise as a Royal Canadian Mounted Police spokesman said Tuesday, "it's the ultimate skiing with the ultimate risk."

Sarah Love, Mountain Zone Staff

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