On February 22, 2021, a group of two splitboarders and one skier toured from Taggart Lake trailhead up 25 Short (so named because the peak is 25 feet short of 10,000) to descend the Broken Thumb Couloir into Avalanche Canyon. This is a very narrow chute, and the descent normally involves a 50- to 100-foot rappel in the lower half.

A little after 11 a.m., a 33-year-old rider was leading the group down through steep trees and rocky terrain to the entrance of the couloir when he triggered an avalanche that carried him down the confined, rocky couloir and over the rappel zone. He was carried about 800 vertical feet and stopped by a tree, suffering significant trauma, and was buried. His friends located him with a transceiver but could not revive him.

The avalanche was a recent wind slab estimated at 150 to 200 feet wide and two feet deep at the maximum. It ran 1,100 vertical feet. This relatively small avalanche occurred directly above steep, rocky, and vertical terrain and took the snowboarder on an unsurvivable fall.

ANALYSIS

All the individuals involved in this incident had at least a Level 1 avalanche class and significant experience in avalanche terrain.

Beginning February 12, snow fell daily in this area up to February 22, with an estimated 65 inches recorded at the Surprise Meadow snow station, about two miles north of the accident site. In the week prior, many avalanches were reported in Grand Teton National Park. The Bridger-Teton Avalanche Center’s hazard rating for February 22 was Considerable (Level 3 out of 5).

This accident occurred on serious terrain above a large cliff. Due to the exposure, this was not only an avalanche accident but also a mountaineering accident. Two other avalanche fatalities happened in the Bridger-Teton forecast area earlier in the same week, and all of them occurred in steep terrain exposed to terrain traps. On February 17, a group of nine snowmobilers was riding in the Salt River Range, southeast of Alpine, when a soft slab avalanche caught seven members of the party.

Two were buried and rescued, but one was swept with his sled into a treed area at the base of the slope and was buried in four to five feet of debris.

On February 18, a group six snowboarders built a jump above a steep bank in the backcountry near Togwotee Pass. A 31-year-male made the first jump and triggered a slab avalanche on the 42-degree bank. He was carried to the creek bottom at the base of the bank and was buried under nine feet of avalanche debris.

When natural and human-triggered avalanches are happening, terrain selection is essential. (Source: Bridger-Teton Avalanche Center.)

Read the full report prepared by Grand Teton National Park rangers.