Avalanche Incident
Avalanche Incident
Inspiration Pass Avalanche Accident
On the afternoon of Saturday, January 24, 1998, a 21-year old snowmobiler was killed in an avalanche in Northwestern Montana at Inspiration Pass in the Swan Mountain Range, south of the community of Swan Lake and southeast of Kalispell, Montana. The victim from Columbia Falls, Montana was riding with another young companion along the crest of the Swan Range. They had reached the 7000 foot elevation site by traveling up the Soup Creek drainage on the west face of the Swans.
The victim triggered the slide when he dropped into an irregular shaped bowl on the east face of the range. The resulting avalanche was approx. 1200 feet wide with a variable crown fracture depth of 1-5 feet and ran approx. 600 slope feet. The crown fracture was irregular in shape running sometime along the ridge, then down to tree outcrops, around a rock face, then back up toward the ridge. Aspect was generally southeasterly. Slope angle from the stauchwall to the crown was 35 degrees. The failing slab covered almost all of the open slope top-to-bottom with debris, often blocky, deposited in the trees below.
Like many areas in the Northwest and Western Canada, Northwestern Montana has had below-normal snowfall this season. Dry conditions in November produced a shallow snowpack with considerable weaknesses associated with buried facets and surface hoar. Snowfall amounts increased somewhat in December. Between Christmas and New Years the mountain snowpack developed melt-freeze ice layers associated with freezing rain events well up to 7000 feet. These ice layers and subsequent warmer and deeper snow began to give the snowpack a base, yet the weakly bonded basal facet layer and the buried surface hoar layer slightly above persisted in most all areas above 5500 feet in elevation.
During the week before the avalanche this portion of the Swan Range and the neighboring Mission Range had received significant amounts of new snowfall. The snotel site at Noisy Basin, 25 miles to the north from the avalanche, had recorded over. 3 inches of snow water equivalent between Monday and Saturday morning. Friday night prior to the avalanche winds in the areas were reported to be strong from the west/southwest. Friday and Saturday also saw temperatures warming from the low 20's to the high 20's and low 30's.
The crown fracture was variably loaded with recent wind deposited snow and the failing weak layer appears to have been a weakly bonded layer of buried facets and surface hoar. Our time at the site was very late in the day and we were limited in our investigation before nightfall. The bed surface was a much denser layer approx. 1 foot above the ground.
The victim was totally buried approx 5.5 feet and was reported to be missing his helmet. He suffered facial lacerations when he slid through a clump of trees. Exact cause of death is unknown at this time. The final location of the snowmobile after the avalanche is also unknown currently. Both the victim and his companion were wearing transceivers, but the witnessing companion was unfamiliar and untrained in how to use the instrument.
There was another party of snowmobilers in the area and they also witnessed the slide. One of these riders had a transceiver but it operated on the old 2275 frequency and the victim's beacon was a single frequency 457. This rider however took the companion's transceiver, conducted a search, and was able to locate the buried victim. He was uncovered lifeless approx 60 minutes after being buried in the avalanche.
Soon after the avalanche a cell phone call from the other party on site alerted both Lake and Flathead County authorities of the accident. There was a period of confusion as to the exact location so both counties began to mobilize search and rescue efforts. The west face of the Swan lies in Lake County while the east face is Flathead. The falling of nightfall and the confirmation of a fatality led the Flathead authorities to suspend the recovery Saturday night and the body was subsequently recovered by ground Sunday mid-day.
The location of this avalanche is very typical to the terrain that snowmobilers are currently capable of accessing. It is high and deep in with routes that require strong machines and very capable riders. It is imperative that these parties be prepared with both the equipment and training to conduct a search and rescue effort in the event of a slide. As in this case an outside organized rescue effort is many, many hours away.
We also encourage these parties to develop at least a rudimentary understanding of snow stability evaluation. It is impossible to keep snowmobilers and skiers from playing in avalanche terrain. With a basic understanding of what makes avalanche terrain however, and a somewhat notion of the effects of weather on snow stability, they will stand a much better chance of timing their play and avoiding accidents.
Stan Bones
Glacier Country Avalanche Center
Flathead National Forest
gcac@digisys.net
SNOWMOBILER KILLED BY AVALANCHE IN THE SWAN
BEN LONG, The Daily Inter Lake.
A Columbia Falls man snowmobile rider was killed by an avalanche Saturday afternoon while riding near the Swan Divide.
A 21-year-old Columbia Falls man was killed in the slide, which occurred near Inspiration Pass northwest of Condon. The slide occurred about 2 p.m. and the sixth avalanche fatality this winter in Montana's high country.
Members of the Flathead, Lake county search and rescue squads and the Flathead Nordic Ski Patrol tried to reach the scene Saturday but were turned back by extreme avalanche risk and darkness.
The avalanche occurred near the crest of the Swan Divide, about 10 miles from a passable road, Sgt. Glen Fulton said.
"Conditions are very treacherous," he said Saturday evening. "It's going very slow."
ALERT helicopter was sent to the scen, but called off when rescuers learned there were no other injuries, beside the fatality.
"We didn't have any reason to send them in. Then we started losing daylight," Fulton said. Efforts to recover the body would resume at first daylight, Fulton said.
Fulton didn't know how many people were in the party or exactly where the avalanche struck. However, from the snowmobilers' report, the slide occurred just outside the wilderness boundry, Fulton said.
Avalanches have been particularly wicked this winter in Montana. Saturday's slide marked the sixth avalanche victim killed in Montana this winter - five snowmobile riders and one winter mountaineer.
The climber was swept to his death while climbing in the Mission Mountain WIlderness. Four snowmobile riders died near Park City and another died in the Bitterroot.
The Glacier Country Avalanche Center telephone hotline listed avalanche danger as "moderate" above 5,500 feet in northwwestern Montana on Saturday. That's somewhat less than the "considerable" avalanche rating of earlier in the weak.
The hotline, which was updated on Friday morning, noted that fresh snow had fallen in the Swan Mountains this week. Fresh snow can be unstable, until it settles.
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