Vail & Summit County
AvalancheJason Konigsberg · Dec 24, 2017 · Vail & Summit County
Weather
Still windy especially at ridgetop but wind loading was light in general. There were still isolated terrain features receiving good amounts of wind-drifted snow but not many plumes off ridges or slopewide loading. Clouds increased throughout the day.
Snowpack
Last night's wind did a lot of damage to the alpine with westerly slopes stripped back to rock and many other slopes showing the effects of sustained strong winds. Drifts of snow were concentrated on cross-loaded terrain features in the alpine and downslope of normal loading. Easterly slopes near treeline did not look to be as ravaged and thicker slabs that are cohesive across a slope may exist.---I dug on a southerly slope near treeline and found a very poor snowpack structure. The slab was only about 10 inches thick but this slab sits on facets above a crust above more facets. The crust is so poorly bonded to surrounding snow layers it seems to be just floating in the snowpack. Southerly slopes have a Persistent Slab structure and any significant load would make conditions touchy. This crust/facet combo also exists on east slopes and I think that this layer was responsible for most of the natural activity on Saturday night.---On a near treeline north slope I found a 1 meter deep snowpack that consisted of a 35 cms slab over all sorts of junk- facets, depth hoar, more facets. The whole snowpack is soft with no hard layers and still lacks a slab that is strong enough to communicate a fracture. Any added slab would also make northerly slopes touchy.
Avalanche
Relatively few avalanches in the backcountry for the amount of snow and wind we got. The wind was just not at prime loading speeds. I believe most avalanches happened during a few hours when precip intensity was high.