Vail & Summit County

Avalanche

Jeremy Primmer · Nov 15, 2021 · Vail & Summit County

Weather

Warm and sunny conditions, above freezing on southerlies as we hiked up. Light breeze at ridge top and below freezing on the east aspect of the ridge at 12,000'.

Snowpack

-We noted previously wind-drifted snow on north to northeast through east-facing aspects near and above the treeline. This was from our strong northwest winds a few days ago. In general, these slabs sit over weaker layers near the ground, keeping our persistent slab problem at play on these aspects. There was a lot of wind deposited snow on east-facing aspects from the 11/10 storm. These east-facing slopes look very filled in for this time of the year. We found a more continuous snowpack on southeast facing terrain than we were expecting. Although still very thin in places, southeast-facing catchment areas such as gullies had a snowpack up 70 cm deep. ---We dug a pit above the treeline on a northeast aspect that was wind-loaded. We found 80cm of snow with a pencil hard wind slab sitting on top of weaker faceted snow. We did two extended column tests and got propagating results with moderate force in both. One test failed at the ground in basal facets, and the other failed just underneath a melt-freeze crust sitting on top of basal facets. ---We found a relatively stable snowpack on southerlies. Digging on a south-facing slope near the treeline in a small wind-loaded pocket, we found 54 cm of snow with the top 37cm smoothly transitioning from 1 finger to pencil hard. Under this, there were a couple of decomposing crusts. ---On a more protected southwest-facing slope, we dug a pit and found a more faceted snowpack. Our pit had wind-packed grains sitting on top of buried near surface facets. Lower down in the snowpack, we got a propagating result with hard force on a decomposing crust 15cm up from the ground. At the bottom 12cm of the pit, there was fist hard moist rounding facets. We are not sure how representative this pit is of other near treeline southwest-facing aspects. ---Southerlies had a moist surface by the early afternoon. This will create a slick surface after the temperature drops that new snow will have a hard time bonding to during the next storm. ---We saw some small loose wet in steep south-facing terrain that started in rock bands from a couple of days ago and saw one small rollerball from today on south facing terrain.

Avalanche

Old avalanches that most likely ran on 11/10 and failed due to windloading.