Southern San Juan
AvalancheAnonymous · Feb 8, 2014 · Southern San Juan
Weather
Snowing lightly all day, with approx. 2†of accumulation during the tour. Light wind, but no evidence of loading. Approx 5†of overnight snow on the skin track. 2-3’ of snow had fallen during the past few days, and at least 5' had fallen since the January drought ended.
Snowpack
Over the past week and a half approx. 3’ of settled snow had been deposited over January’s old snow surface. Upper layers were of fist density or less and cohesionless with gradual increases in density until the New snow/old snow interface. This interface was extremely evident, with abrupt transition to 1F density. Performed an ECT at approx. 10,800’ on a NE aspect approx. 150m from slide trigger point. Results were negative, with no failure or propagation. We had also performed several hasty column isolations with a ski pole in other areas to test new/old snow interface and all provided Q3 sheers after moderate to more than normal initiation force. One member of the party had skied the exact zone on Wednesday of this week, and one had skied it on both Tuesday and Wednesday. Close friends, who had been consulted before the tour, had also been skiing the zone Sunday, Monday, and Friday as well. Skier triggered slide activity had occurred earlier in the week, but the general trend seemed to be slowly moving towards stability and less reactivity with the new/old snow interface. The slope later failed at the new/old snow interface (the January drought layer), which served as the bed surface for the entire slide.
Avalanche
Three skiers participated in the tour. During the initial approach we discussed numerous safety considerations such as the snowpack composition, avalanche activity earlier in the week, the CAIC report and rating of “Considerable†for the day, and CDOT’s lack of results from control work on the pass. Our combined 3+ decades of backcountry experience, familiarity with the area, formal avalanche education, and negative findings from pit work and hasty column isolations led us to believe the day could be enjoyed with a relative sense of security. We agreed that despite the recent snow load and persistent slab problem, if we skied with caution, were judicious in our route selection, and avoided hazards such as convexities and large open areas we would be ok. There are no slide paths within this area, no established starting zones, and relatively little effect from wind loading. The pitch averages in the high 30s, and the terrain is heavily to moderately treed overall, and contains several cliff bands. Our first run went without incident, skiing a 1000’ NE facing treed run with occasional small openings/shots. For our second lap we skied approximately 200’ to skier’s left of our first run. One at a time, we dropped in from the ridge, regrouping approx. 200’ below the ridgeline, above a relatively narrow, 100’ long shot. In hindsight, we all agree that this shot appeared to be no different than what we, and our friends, had been skiing all week. Skier 1 dropped into the shot first, making several turns in mid-thigh deep powder. After approx. 100’ of skiing she shot ended, so he pulled out left back into the thick trees. Looking over his shoulder, he saw the slope above him fracture. He reached for a nearby tree, but was swept. Dragged head first down the slope he collided with several large trees in a tree stand, hitting his arm, thigh, and head. He was wearing a helmet. During the collision both skis and poles (which did not have straps) were stripped from him. Now spun around sideways, the slide completely enveloped him as it continued carrying him down the slope and over a 30’ cliff. After landing on the steep apron below the cliff he felt the slide beginning to slow, and thrust his face into his elbow to create an air pocket. During this motion he unconsciously spun into self-arrest position with his face into the slope, his feet pointed downhill and digging in. It’s unclear if it was the self-arrest, good karma, or just plain luck, but skier 1 came to a sudden stop on the steep apron below the cliff while the avalanche continued down without him. Uninjured, he stood up and yelled to his partners with a euphoric sense of total disbelief that he was OK. Skiers 2 and 3 observed the slide from the first regrouping spot appox. 200’ below the ridgeline. When skier 1 came to a stop at the bottom of the shot and triggered the slide, it propagated up the entire shot, but did not entrain their safe spot. They saw the slope break and skier 1 get swept, but he immediately disappeared from view. Moments later they heard Skier 1 yelling he was OK. They then took photos of the initial crown and shot (see attached). On their way down to Skier 1 they were able to locate both skis and one pole from Skier 1. They estimate he had been carried 150’ from the trigger point. Skier 1 took photos from his arresting point (see attached). After reaching Skier 1, the party regrouped and made our way down. Assessing the scale of the avalanche filled us with an incredible sense of awe. The initial shot had been a relatively limited D2 with a 30’ wide crown. But, the terrain below the cliff skier 1 was carried over was exactly what we had planned to avoid: relatively open. In this more open terrain, the slide propagated considerably becoming a D3 and approx. 3-400’ across. Overall, the slide ran appox 800 vertical feet with multiple crowns varying from 2-4’. The snowpack failed at the interface of the new snow with the January drought layer, which served as the bed surface across the entire slide. The powder blast on the trees reached over 15’ tall. Trees up to 4†in diameter were broken. It is worth reiterating that the entire run of the avalanche was within a treed area, not a slide path.