Large Cornice/wind slab failure on the ridge of Rooster Comb beyond the two combs above the 2nd bench. This area did not appear to be corniced or overhanging, and was in a saddle formed in between two cornice formations. The snow broke appx. 6 feet back from the edge, and was roughly the size of a small bus. It entrained significant snow on its decent but did not trigger a deeper slab below. The fall line was also well anchored. Run out was several hundred feet with debris appx 4-6 feet deep, 60 feet wide and 200 feet long.
No one was buried or partially buried in this accident.
Did you observe any avalanches?
Size 2: Could bury, injure, or kill a person
See description above.
Signs of Unstable Snow
Did you see shooting cracks?
Did you experience collapsing or whumpfing?
We were aware of spooky conditions and travelled very cautiously to gain the ridge. Our goal was a well anchored area of rooster comb where we believed there would be an opening in the cornices and no opportunity to produce a large avalanche based on our terrain selection. The weather was below freezing with heavy clouds and moderate fog, preventing solar but also reducing visibility significantly.
From the side as we approached along the ridge, the area where we intended to drop appeared fully attached to the slope. No overhang or curl as we had seen the cornices as we travelled the ridge. This may have been an optical illusion due to poor visibility, or it may have been a wind loaded shelf that we misjudged.
As we regrouped, still everyone 5-6 feet or more from the edge, the snow collapsed suddenly and violently. Our group was 5 people, spaced out but close enough together to trigger the release.
4 of 5 fell with/behind the cornice. 1 person remained above and had eyes on the situation. 3 people were able to gain control and stop sliding at the top the slope. 1 person was carried appx 20 feet and was able to grab a tree before momentum was gained. No serious injuries were incurred.
Observed Avalanche Problem #1:
Triggered from 6 feet away from edge. No solar and temps below freezing on Tuesday. No signs of roller balls, whoomphs or cracks. The snow collapsed under gradual loading as we assessed our drop believing that we were in a safe area. Poor visibility and/or wind drifted snow may have created an optical illusion from the side angle that prevented us from seeing the reality of what we were approaching. Two holes that appeared after the event may have acted as trigger points against the rock formation. Our groups spacing along the ridge may have also triggered one of the cornices to the side and caused it to propagate along the ridge.