Vail & Summit County
AvalancheKreston Rohrig, Mike Floyd · Dec 12, 2020 · Vail & Summit County
Weather
Grey day with very light snow. Southwest winds had some bite, but were not overly strong. Wind-transport was light to moderate, mainly due to the lack of fresh snow.
Snowpack
Below treeline the snowpack in this area is very thin and fully faceted below the new snow. On very steep unsupported slopes it was easy to initiate small loose snow avalanches that "sluff" out the 30-40cm snowpack. Even ski penetration was going straight to the ground. Higher up the mountain near treeline, the snowpack was a little deeper and the remnants of a crust and denser slab helped keep us afloat. In areas that were not actively or previously wind-drifted the total depth averaged around 50cm and was mostly faceted. The terrain above treeline looked very thin and previously wind-hammered. Small cornices were forming just below ridgeline but rocks were still showing in the path, so new slab formation did not extend very far. We dug in a couple places around 11800' on an east aspect in areas with recent wind-loading. Depth was around 100cm, with very weak faceted layers just below the new snow. I had a super reactive crust/facet layer (ECTP4) in the upper portion of the snowpack, but this layer was not widespread (not found in the other pit nearby). Below the upper 30cm of weak snow, the mid-pack slabs were still very hard and intact (good sliding surface).
Avalanche
We intentionally triggered some very small loose snow (facet sluffs) on steep, unsupported, northerly-facing slopes. These were harmless and easy to manage, but did run to the ground.