Vail & Summit County

Snowpack

Andrew McWilliams · Dec 30, 2024 · Vail & Summit County

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Weather

Broken skies became obscured by midday and there was light snowfall with moderate westerly winds. The temperatures dropped all day and reached the single digits by late afternoon. When I returned to my car there was a trace of snow on it.

Snowpack

Below about 9,500 feet there was only 20 to 30cm of snow on the ground. Around 10,000 feet the depth increased to about 60cm. Between about 10,000 and 11,000 feet there were widespread localized collapses. Above about 11,000 the snow depth was close to a meter. The collapses were less frequent, but louder and involving larger areas. When I approached a steep east-facing and southeast-facing slope around 11,300 feet I got shooting cracks that extended over 100 feet in front of my skis. I didn't trigger any slides, but I did see a recent slide at ridgecrest near where I observed the shooting cracks. It looked like a Storm Slab avalanche that ran a few days ago since the debris was mostly obscured by new snow. The slide ran on a melt-freeze crust below the storm snow. I dug a snowpit between the avalanche and one of the slopes where I had shooting crack and rumbling collapse. There was about 40cm of storm snow resting on two crusts with facets sandwiched between and above and below the crusts. Below these facet-crust combinations there was about 40cm of faceted snow resting on the ground. In my snowpit, I got a propagating result after 10 taps from the elbow in an Extended Column Test that failed in faceted snow directly below the lowest crust. This says to me that even though I saw a recent Storm Slab avalanche, that Persistent Slab avalanches are the primary concern moving forward. Unfortunately, poor visibility prevented me from seeing any other recent avalanche activity across the valley. Given my snowpit test and significant cracking and collapsing, you'll be able to easily trigger avalanches for at least a few more days. If we get another storm soon, it will likely keep the danger elevated.