Vail & Summit County
AvalancheAnonymous · Mar 23, 2019 · Vail & Summit County
Weather
8:00AM, 12,000 feet, west facing, base of couloir: 25 degrees, overcast, 5-10mph south southwest wind 8:45AM, 12,600 feet, west facing, crux of couloir approaching ridgeline: 20 degrees, overcast, 20-25 mph west southwest wind gusts with some blowing snow
Snowpack
Our objective was Shit for Brains couloir. It is west facing and runs from approximately 12,000-13,000 feet in elevation. The avalanche forecast for that day was moderate ATL/AT and low BTL. The forecast discussion indicated a recession of the persistent slab problem, but a need to watch for small, isolated pockets of wind loading near ridgeline on the Continental Divide. We observed an old crown in Dog Leg, as well as debris from a previous slide down SFB. Our group discussed this, and decided that the persistent slab danger was a a manageable risk due to the previous slide. We encountered 4 inches of light new snow on a 2-3cm breakable suncrust. There were no signs of instability or wind loading during the first 600 feet of ascent. As we neared 12,500 feet we noticed that the winds began to gust stronger, coming out of the southwest. At 12,600 feet as we neared the crux of the couloir, our group leader encountered a pocket of wind loaded snow approximately 18in deep. The accident occurred before he could turn around to discuss his findings with the group.
Avalanche
3 skiers decided to ascend Shit for Brains early Saturday morning. Skier 3 invited another friend, but the group quickly turned into 6. All 6 skiers were apprehensive about the group size. After a discussion, they agreed to ascend the same bootpack, but split into 2 groups and descend different lines. Retrospectively, they wish they had split into 2 groups at the base of the line. They reached 12,000 feet at the base of the couloir and began ascent at 8am. All 6 skiers were evenly spread, with about with 10-15 feet between each person. Skier 1, leading the group, encountered a pocket of wind loaded snow at the crux, a convex rollover that approaches 45 degrees. The snow went from approximately 4in to 18in. Noting the change in the snowpack, he decided to take a few steps laterally across the couloir. Before he could turn around to discuss this with his group, he saw a fracture 10-15 feet above him. We think the crown ran across the entire couloir and was 16-18in deep. He called "SLIDE!" to the rest of the group. All skiers tried to step against the rock walls as best they could. Skiers 2, 4, and 6 were able to avoid being swept. Skiers 1, 3, and 5 were hit with a wave of snow and tumbled violently down the line. Skier 3 was able to open her eyes, and saw periods of light and dark as she was swept underneath the snow. When the avalanche stopped all 3 skiers were on top (with no partial burials). Skier 1 was about 60 feet above skier 3, who was about 50 feet above skier 6 at the base of the debris. The group quickly communicated and took a head count. After determining there were no burials, everyone met at the bottom near skier 6. Skiers 4 and 6 were bleeding and needed medical attention. Skier 1 called ski patrol to report the slide. The group then retrieved a lost ski from lower in the basin below and headed to ski patrol at Arapahoe Basin. The avalanche did not step down to deeper layers.