Gunnison
SnowpackAnonymous · Nov 26, 2013 · Gunnison
Weather
Cold, calm, and clear.
Snowpack
At 12:20 pm this afternoon, we triggered an avalanche in a couloir on the north face of Mount Axtell in Crested Butte, Colorado. We were bootpacking up the couloir with the intent of skiing the Shark Fin, the next couloir to the east.
My skiing partner and I set out from the Kebler Pass parking lot with the intent of skiing the "Shark Fin" couloir on Mt. Axtell, a north facing couloir just to the west of point 11658' on the east ridge of Mt. Axtell. Upon reaching Green Lake, we decided that the best route of ascent would be to skin up the apron and bootpack up the couloir. We noticed old buried debris on the apron, presumably from an earlier storm cycle. There were small wind loaded pockets on the climbers left side of the apron that we deemed inconsequential due to their sporadic and isolated nature. As we ascended the bottom of the couloir, we were constantly evaluating the presence of wind slabs and persistent slabs. We did not observe a wind slab near the surface in the bottom of the couloir, but we did observe about 30 cm of loose, unconsolidated new snow. This layer was not wind affected.
While ascending, we decided to diverge from the Shark Fin and climb the couloir just to the climbers right, which we thought would provide easier travel. Throughout the climb, no wind slab was observed and stability was good. There was no whumphing or shooting cracks, and informal tests showed no results.
Nearing the top of the couloir, about 20m before reaching the ridge and gentler terrain, we observed a change in the density of the surface layer. Shortly thereafter, there was a large collapse that produced cracks about 3m above the highest climber. We were nearing the top of the couloir and exit to the sides would have involved climbing near vertical rock. Because the slope cracked but did not move, we gained a false confidence in the strength of the snowpack. A few steps later, the slope collapsed again and began to slide.
Climber 1 was carried about 200 feet and was able to escape to the skiers right as the slide moved past. Climber 2 was carried an additional 200 feet and escaped to the skiers right as well. There were no injuries or burials. The slide continued another 600 vertical feet and the deposition zone was located in the large apron below the couloir. There were rocks and small trees in the debris.
My skiing partner and I set out from the Kebler Pass parking lot with the intent of skiing the "Shark Fin" couloir on Mt. Axtell, a north facing couloir just to the west of point 11658' on the east ridge of Mt. Axtell. Upon reaching Green Lake, we decided that the best route of ascent would be to skin up the apron and bootpack up the couloir. We noticed old buried debris on the apron, presumably from an earlier storm cycle. There were small wind loaded pockets on the climbers left side of the apron that we deemed inconsequential due to their sporadic and isolated nature. As we ascended the bottom of the couloir, we were constantly evaluating the presence of wind slabs and persistent slabs. We did not observe a wind slab near the surface in the bottom of the couloir, but we did observe about 30 cm of loose, unconsolidated new snow. This layer was not wind affected.
While ascending, we decided to diverge from the Shark Fin and climb the couloir just to the climbers right, which we thought would provide easier travel. Throughout the climb, no wind slab was observed and stability was good. There was no whumphing or shooting cracks, and informal tests showed no results.
Nearing the top of the couloir, about 20m before reaching the ridge and gentler terrain, we observed a change in the density of the surface layer. Shortly thereafter, there was a large collapse that produced cracks about 3m above the highest climber. We were nearing the top of the couloir and exit to the sides would have involved climbing near vertical rock. Because the slope cracked but did not move, we gained a false confidence in the strength of the snowpack. A few steps later, the slope collapsed again and began to slide.
Climber 1 was carried about 200 feet and was able to escape to the skiers right as the slide moved past. Climber 2 was carried an additional 200 feet and escaped to the skiers right as well. There were no injuries or burials. The slide continued another 600 vertical feet and the deposition zone was located in the large apron below the couloir. There were rocks and small trees in the debris.