Vail & Summit County
AvalancheAndrew McWilliams · Apr 12, 2023 · Vail & Summit County
Weather
A few clouds in the morning with above-freezing temperatures overnight. Skies became broken by about 1 pm and the wind was moderate from the southwest. When I returned to the truck below 9000 feet at about 4 pm, the temperature was 60 degrees F.
Snowpack
At low elevations in the morning, below 10,000 feet, the snow was mostly supportable to travel with a decent surface freeze from radiational cooling. I only broke deeply into the snowpack near trees, rocks, and bushes. By the late afternoon, the same low-elevation slopes were generally unsupportable with cohesionless, isothermic snow. I broke deeply into the snowpack in most areas, especially near trees, rocks, and bushes. I ascended westerly slopes to about 11,600 feet. Travel became more supportable at about 11,000 feet where I broke into the snowpack very rarely. In a pit below treeline just below 11,000 feet on a northwest-facing slope, I found a 160cm snowpack with ice bodies into the depth hoar layer and moist snow from the surface to the ground. Near treeline on a north-facing slope the top 75cm of snow was moist to wet with dry snow below this level. The total depth of this pit was 315cm. On a southeast-facing slope near treeline, the snow was 270cm deep with wet snow down to about 180cm. The snow was moist below this level. The interface was an older ice layer that was still dry, but quickly became wet when exposed. Water was dripping out of my ECT column at this interface. The exposed pit wall became very wet with areas of pooling water becoming slushy and water was easily squeezed out of the snow. All three snowpits had non-propagating results in Extended Column Tests (ECT) within the top 30cm of the snowpack at the interface with moist layers and wet to very wet layers with pooling water. I observed a multitude of recent Loose Wet and Wet Slab avalanches that likely ran during the warm-up the past two days.
Avalanche
I saw too many Loose Wet avalanches to count on every aspect near and below treeline. I did not observe any Loose Wet avalanches on north-facing slopes above treeline. I saw at least three Wet Slab avalanches on east through south to west aspects near and above treeline. Most avalanches appeared to have run yesterday, although I saw a small number that may have run today.