Vail & Summit County
AvalancheDrew Gibson · May 30, 2019 · Vail & Summit County
Weather
Above treeline 12k to 13k. Partly cloudy, air temp hovering around 0F. Calm to Light cold wind on ridge crest, no transport. Heavier cloud cover moved in approx 1045 and the greenhouse effect turned up.
Snowpack
Above treeline approx 4"-6" new on ridge crest, no evidence of wind loading, small cornices observed on S face, but were hard and mostly preexisting . Old/new interface seemed fairly well bonded when cold despite the planar interface. Once the greenhouse effect picked up the new snow didn't want to bond on steeper slopes (>35deg). The old snow was beginning to warm even with the new on it due to radiation but boot pen was only approx 10cm at 12500 at 1130.
Avalanche
AS-LW-R1-D2-O/I Quandary North Face ~12600 ~38-40deg No one caught Triggered off of sluff. 4"-6" of new snow was rafting under skis in the upper path and when pushed en trained snow below it. Very slow moving at first, but the path constricts half way down so the en trained snow picked up quite a bit of speed by the time it passed the choke and hit the fan at the bottom. Approx debris depth at tow to 50cm-70cm, football and basketball sized chunks. No slab pull out observed off sides of debris track. Track of path was isolated to the fallline of the trigger. Rated Size 2 due to the terrain trap and amount of debris at the bottom. Debris arrested on the fan and did not run to the flats below. Bed surface was soft and supportive to ski on. Observed from Highway 9 Red Mountain on Hoosier Ridge (above Blue River) SS-N-R1-D2-U NW ~12800 Looked like it was fresh this morning. Looks like a Soft Slab, could see flanks and crown through binoculars, but hard to say.