Weather and Snowpack Summary:
5-15cm of new snow fell over the area above 900m on the 25th (two days prior). Rime ice also accumulated on high cliffs in the area during this time. The slough originated high on the cliffs above the couloir, on an unknown slope. Observations indicate small amounts of rime and loose snow poured off surrounding cliffs in the two days leading up to the incident. It is believed that the slough came off of a cliffside without an accumulated snowpack.

The Haines Avalanche Information Center snowpack summary for the date (issued April 20th) reported low danger, with "Wet Loose Slides" as the biggest threat. Details included, "Wet loose slides will be a primary concern on many steep slopes. These can entrain quite a bit a snow and carry you into dangerous situations. Watch out on any slope where the new snow softens to ankle-deep or more."

A number of days leading up to the 27th had the mountain shrouded in clouds, thus preventing solar radiation from reaching the high cliffs above the couloir.

Details of the Incident:

On the final day of a 5-day ski trip, a splitboarder (Skier 1), and an A/T skier (Skier 2) climbed and skied an unnamed couloir they had spotted from the air on the flight in.

The two had scoped out the couloir diligently from the air, and inspected it from below on the 26th. They observed that while other nearby peaks in the sun were shedding loose debris, the peak they planned to ski remained cloaked in a cloud, and that the couloir did not show signs of debris running down it. Further, they reasoned that because the couloir was at high altitude and inset deeply into the mountain, it would receive little solar radiation and maintain a colder snowpack.

The next day, they entered the couloir from below as the sun hit the cliffs on its north side. As they climbed, loose debris from the cliffs above began pouring down the center of the couloir, digging out a runnel. The climbers considered turning back, but reasoned that the debris shed was minor and confined to the runnel, hoping that clouds would build over the summit and limit the solar radiation, as had happened each of the several days before.

They climbed for another hour before full sun hit the couloir. With full sun, temperatures above 5000ft began climbing higher than at any time this season. It was now afternoon, and no cloud had built above the mountain to cool things off. Worried, the two climbers agreed the situation was becoming dangerous, and again discussed turning around, but, lacking an easy escape, they decided to continue to the top of the couloir, since it was less than ten minutes away. Those ten minutes may have made the critical difference in their exposure to slides from above.

The two made it to the top of the couloir at about 6200ft, transitioned their gear, and began riding back down around 2:30pm. By this point, loose debris had stopped falling from the cliffs above, and the skiers focused on controlling their own skier-triggered sloughs (which were not unmanageable since the couloir had been shaded for most of the day). They took turns leading pitches, skiing one at a time from safe zone to safe zone.

After descending approximately 600ft, Skier 2 was standing off to the side of the couloir, watching as Skier 1 carefully descended down towards him. As Skier 1 crossed the runnel at about 5600ft, Skier 2 alerted him of a slide coming down the couloir from above. Skier 1 had only enough time to dig in his ice axe, and face his helmet into the oncoming slide.

Skier 1 was overtaken by debris, and pushed down the couloir past Skier 2, who was far enough off to the side to not be caught.

Skier 1 was able to maintain full self-arrest with his ice axe for most of the 1900ft slide down the couloir, even when he was underneath the moving debris. He credits this with saving his life, as it acted to slow the fall, allowing most of the debris to continue down past him, and to anchor his body to the slope, preventing a rag-doll tumble down the steep couloir.

Near the bottom of the fall, the ice axe was ripped from Skier 1's hands, and he began to tumble violently through the wet slide debris until he came to a stop at the bottom of the couloir's apron, at 3700ft. He was laying twisted on top of a large debris pile, with his snowboard sticking up in the air. His right snowboard binding had broken during the fall, leaving only his left foot attached to the snowboard.

Skier 2 was able to ski cautiously down the couloir to Skier 1 within several minutes. Both were relieved to find that Skier 1 only suffered a sprained ankle, two dislocated shoulders, some minor lacerations to his face, and many bruises. Both skiers are wilderness first responders, and they completed a full patient assessment before deciding not to call in a rescue (both carried SPOT satellite rescue beacons). Skier 1 was able to ski back to camp, and to ski/hike out to the ocean for a pick up the next day.

Analysis:

This is a case of high risk-acceptance and the human factors that cloud judgment. The two climbers/skiers are both experienced ski mountaineers and avalanche safety instructors. They prepared heavily for this descent, and evaluated the conditions as they climbed. They correctly identified the dangers to which they were exposed, and decided to continue climbing anyway, falling into two common human-factor mistakes: they were overly goal-oriented and group-confident.

They correctly assessed that the snow they climbed on was at low-risk of sliding since it had not yet warmed, but also knew that just about anything could come down the cliffs from above. When one would express doubt in the conditions, the other would express confidence, and the two just couldn't commit to a decision to retreat. Knowing it would be hard to ever come back, they wanted to reach the top. Both skiers reported that they each would have turned around much sooner had they been alone, but being with an experienced partner gave them both overconfidence. They were both waiting for the other to make the call to turn around.

Skier 1 mentioned, "As we neared the top, we knew things were getting out of hand. But by that time it was too late to retreat. We were committed to a long, steep, and dangerous descent. We were just hoping the worst case scenario wouldn't happen, and sure enough it did." He added that if the two had agreed beforehand on a threshold for when to turn around, it would have made the decision much easier. For many climbers, that threshold would have been when the first bits of debris came down the couloir.

What may have saved Skier 1's life is that he rode down with his ice axe in hand. Skiing with an axe can possibly increase one's danger for impalement, but in this case it allowed the rider to slow his uncontrolled descent to a survivable level. This is another case where skiers in avalanches have used an axe or whippet to self arrest during the slide, and ended up safely on top of the debris pile.

Couloirs are perhaps the most dangerous lines one can choose to ski. They are steep, narrow, wind loaded, often corniced, and highly prone to falling rocks/ice/debris. They lack safe zones, usually have unforeseen icy sections, and harbor persistent slabs and weak layers due to low sun exposure. Worst of all they are committing, and that is the factor that doomed this climbing party. By the time the danger of full sun exposure had become readily apparent, the two had no escape but to head straight down the couloir, into the zone of most danger.

These two accepted the known high risk of skiing such a large couloir, and one nearly lost his life. Conservative decision making would have precluded entering the couloir at all, and certainly warranted turning around as soon as loose debris slides began.

Both skiers have now reassessed their level of risk acceptance, and stated that they will not enter steep couloirs again.