Vail & Summit County
SnowpackAndrew McWilliams · Dec 18, 2023 · Vail & Summit County
Weather
Broken skies and calm to light winds from the west. Temperatures rose to above freezing by midday after a single-digit start.
Snowpack
The below treeline and near treeline snowpack that I observed today was similar to other areas in Summit County. Northerly and easterly-facing slopes are the most likely place to trigger an avalanche. In this area, it looked more likely to trigger an avalanche near treeline than above treeline. There is a midpack slab of denser snow that ranges from four-finger hard on the Hand Hardness Scale to pencil hard. Below this slab is a layer of faceted snow and dept hoar that is reactive in snowpit tests. Above the slab is a layer of decomposing forms with a preserved surface hoar layer in the middle. There was a layer of surface hoar on the surface as well and the crystals were about 2mm in each layer. There is no slab of the preserved surface hoar layer and it was unreactive in snowpit tests. In all of the snowpits I dug, I got results at the interface between the depth hoar near the ground and a layer of 1mm facets below the slab. I got a propagating result after a few taps from the elbow in Extended Column Tests at the top and bottom of the northerly-facing slope I investigated. I had a sudden collapse in a Compression Test after 3 taps from the elbow at the bottom of the slope. The surface hoar layers had smaller grains at the top of the slope, but were still present. Near the ridgeline, there were multiple dense, thin wind-packed layers above the main slab. Near treeline, the snowpack was supportable to uphill and downhill travel, below treeline the snowpack was supportable in some places and not in others. Westerly slopes had a variable snowpack that quickly transitioned from supportable wind-affected snow to a snowpack completely composed of facets. The only cracking or collapsing I experienced was on the thinner westerly slopes.