Vail & Summit County

Snowpack

Mike Floyd, Kreston Rohrig · Dec 13, 2020 · Vail & Summit County

Weather

Calm, sunny, and cool.

Snowpack

There is an abundance of weak snow, but it lacks the structure that leads to large avalanches. A 60 cm pit dug on a northeast aspect below treeline had 10 cm of weak chained depth hoar on the ground. This is likely the oldest snow from late October or early November. Above this were 10 cm of 1-2 mm fist hard facets. Continuing upward, the snow density was only slightly firmer midpack, barely four finger hardness (not enough for a slab). This 10 cm layer consisted of mostly .5 mm facets. The top of this had 1 mm near-surface faceted grains, formed in the extended dry period before the December 11-12 storm. 25-30 cm of low-density storm snow capped the snowpack. The storm snow was poorly bonded to the older snow where there was a near-surface facet layer. Grain type and interfaces varied across the snowpack but it was all weak snow. No triggered or natural avalanches were observed. In summary, we need one major ingredient for larger avalanches below treeline: a slab.