Alberta, Rocky Mountains, Marmot Basin
On February 22, 1982, at about 12:15 p.m., five downhill skiers traversed to the Sherpa Run just outside the boundary of the Marmot Basin ski area, and just above timberline. As they arrived, they triggered a local slump which spread uphill. They waited a minute or so and saw no slide, so decided to enter the gully.
One skier (23) was ahead, and into the beginning of the gully, when he stopped to take pictures of his friends coming down. The uppermost skier heard and saw the area 300 meters above him fracture and release about the same time as a second skier, who was skiing down, fell just above the first skier. Someone called out a warning and the last three skiers went for the trees at the edge of the gully. Two of them got clear, the third, although caught by the edge of the slide, was able to hold onto some trees as the slide went by. The lowest skier was carried along for 750 meters, through a fringe of trees, and buried among trees about half a meter below the surface. He died from multiple injuries and was found by an avalanche dog three hours and forty minutes later. The second skier was carried down the same distance, was partially buried, and suffered a broken leg. The avalanche size was Class 4 and it had a length of about one kilometer. (Source: Avalanche News, June 1982; D. Stinson, Jasper National Park)
All of the skiers were experienced downhill skiers and some had worked for the Marmot Basin ski area. There had been a high avalanche hazard warning in the Marmot ski area for the previous few days. On February 22, the skies were clear and the temperature was warmer then the previous noontime norm. There was severe lee-slope loading in the area and evidence of an underlying unstable layer in the form of depth hoar.
The accident could most likely have been avoided if the party had retreated after they triggered the first slump instead of continuing down the gully. (Source: D. Stinson, Jasper National Park)
(Editor’s Note: Although this is not a mountaineering accident, it is included to illustrate a typical slab avalanche hazard.)