Hard ski turn unintentionally triggered soft slab avalanche that propagated up and across the concave east aspect of Soldier Nipple, a slope that slides frequently . Fracture line was less than a foot deep at the trigger point but quickly increased to 3 1/2 feet at the crown, clearly wind loaded. The fracture line was approximately 50 feet across but quickly widened to over 100 feet as it pulled out to the ground and ran approximately 600 feet. Interestingly my partner did not appreciate much faceting at the ground layer. I think we were practicing safe protocol and did not plan to ski the aspect that slid. However , I was surprised how easily the slide was triggered and it certainly grabbed our attention. Sorry, no photos.
[FORECASTER COMMENT - We appreciate all observations, especially those that involve avalanches. I talked with the skier who reported this and they commented there were no other signs of instability today other than wind loading at the higher elevations. It sounds like a classic deep slab problem where they triggered the slide from a thinner area of the snowpack (the crown was 1' where it broke out near their skis as they made a hard cut to the left, but quickly propagated above and behind them to a 3.5' crown) and the slide ran on a layer of facets at the ground. They reported the slide snapped some small trees at the bottom of the runout. Thanks again for the report.]
[A UAC forecaster was able to get a photo of the slide on 12/11/2016, the day after it occurred. Additional snowfall and winds filled in much of the visible avalanche path, but the outline of the crown is still visible, and is highlighted in this photo.]