Vail & Summit County
SnowpackAndrew McWilliams · Feb 13, 2024 · Vail & Summit County
Weather
Clear skies had a few clouds by noon. Single-digit temperatures rose into the teens while I was in the field. Calm winds became moderate from the southwest.
Snowpack
I observed a snowpack that was generally a meter or deeper at the upper end of the below-treeline elevation band. I dug quick snowpits on west, northwest, and north aspects. In the northerly-facing pits, the surface hoar layer was obvious about 30cm below the surface. In the pit on the west-facing slope, there was a density and grain size change at this depth, but no surface hoar - likely a layer of near-surface facets. Snowpit test results on the thinner west-facing slope showed a propagating result in the basal facet layer after 15 taps in an Extended Column Test (ECT) with no other results. In a pit on the northwest-facing slope, the snow depth was about 30cm deeper and there was no result in the basal facet layer. I got a non-propagating result in an ECT on the surface hoar layer. The snow above the surface hoar layer was likely not hard enough to propagate a failure. Notably, in this location I found the largest buried surface hoar grains I've seen this winter; ranging from 1 to 2cm. While this layer has not produced a lot of avalanches in the Northern Mountains yet, with wind and snow coming to create a slab and add weight to the snowpack, we will likely start to see avalanches fail at this interface.