AVALANCHE

New Hampshire, Mount Washington, Tuckerman Ravine

On March 30, 1990, the Mount Washington area received about 20 cm of new snow, with winds greater than 65 kph from the south. The winds continued through the night.

At 0800 the next morning, with 20-40 cm of overnight wind deposited snow noted in gullies and catchment areas, USFS Snow Rangers stationed in Tuckerman Ravine posted avalanche hazards as “HIGH”, unchanged from the previous day, for all the skiing routes above the Little Headwall.” This information is prominently displayed in two places: at the trailhead by the AMC base camp in Pinkham Notch, and at the Hermit Lake shelter at the base of the ravine.

At 1000, a nearby gully (Express) avalanched spontaneously. About the same time, we observed a solitary skier, carrying his skis, climbing near the top of Left Gully, which rises about 275 meters from the floor of the ravine toward the southwest. Two additional skiers were about 180 meters below him. Because of the highly unstable conditions, and the cornice at the top of the gully, we monitored the progress of the three closely. The average slope was about 30 degrees and was steeper at the top where it ran into the cornice.

Our radio reported that another gully (Dodge’s) avalanched naturally, just as the uppermost skier was putting on his skis below the cornice. He then started descending traverse and initiated a turn on the 40+ degree slope. Immediately, the entire upper third of the gully erupted in a soft slab avalanche, leaving a 35 cm crown line.

The dust cloud obscured vision from below while the slide ran the full length of the gully. Scouring the snow cover down to the sliding surface of frozen granular, the slide split into two deposition zones, each about 75 meters long, 40 meters across, and five meters deep at the toe. We observed the entire episode to take about nine seconds. The distance traveled was about 600 meters, thus the slide had an average velocity of 240 kph.

The skier was sitting on the snow at the upper end of the left deposition zone. Other than having the wind knocked out of him, there was no evidence of immediate or developing trauma. He was unscathed except for bruises and loss of a ski. We saw that his trajectory took him across a large boulder that split the slide. During the slide, he was tumbled and intermittently buried, and was convinced he would not survive.

As the day progressed, four additional large avalanches were observed, with three of them initiated by skiers. By sheer good luck, none was directly involved. (Source: Roger Damon, Jr., Mount Washington Ski Patrol, NSPS National Avalanche Instructor)

Analysis

The victim’s awareness of avalanches was nil, and he had not noticed either of the signboards posting the current assessment of avalanche hazard. The two skiers below him were far enough to the right side to avoid involvement. They continued their ascent, and were a cause for concern for some time.

To avoid such accidents, one needs to have: (a) an appreciation of the effects of terrain, weather, and wind that combine to create avalanche hazards, and (b) skills in individual conduct in avalanche-prone terrain, including avalanche recognition, route selection, safety precautions, using islands of protection, carrying location indicating devices, mutual observation, and immediate actions if a party member is avalanched.

This episode involved a solo skier who was above anyone who would have observed his “last seen point.” Thus, had he been buried, a successful rescue would have been arduous at best.

It typifies the avalanche accidents that usually result in injury and/or fatality. It also highlights our unique situation in Tuckerman Ravine, where usage is counted in the thousands of people on a busy weekend. Some of those believe that posted warnings are obviously meant for people other than themselves. (Source: Roger Damon, Jr., Mount Washington Ski Patrol, NSPS National Avalanche Instructor)

(Editors Note: This is not a climbing accident, but is presented as an example of how skiers used to groomed ski areas can quickly get in trouble when out of that controlled mountain environment.)