Vail & Summit County
AvalancheAndrew McWilliams · Nov 26, 2024 · Vail & Summit County
Weather
Snow all day with light winds and temperatures in the 20s. About 3 or 4 inches of snow was on my car when I returned from the field.
Snowpack
When I started hiking there was about 10 inches of storm snow on the ground. By the time I left the field there was over a foot. I observed cracking on nearly every steep slope I encountered while ascending northeast and east-facing slopes, but surprisingly few collapses given how reactive the snowpack was. I was able to trigger multiple avalanches failing at the interface of the basal facets and the storm snow. Where I traveled and dug snowpits there was a surprising lack of midpack layers in the snow. I wonder if there had been a thicker midpack, if the avalanches would have run on a different interface. That said, I triggered one test slope by skiing along the edge of the slope and that slide sympathetically released another one. On my way back to the car, I remotely triggered two more steep slopes by just approaching the rollover at the top. All of the slides were small in size. In snowpits, there was no surprise that I got a propagating result after six taps from the wrist at the basal facet interface in an Extended Column Test (ECT). I also consistently had a result within the storm snow in ECTs, but these were non-propagating. With additional snow overnight, that layer could become an issue as well. However, it seems likely that almost any avalanche in this area would step down to basal facets. I did not observe above treeline due to bad visibility, but I got a surprising lack of avalanche activity as I ascended the ridge and easily kicked off large pieces of cornice. I think the light winds were not efficiently loading snow onto the slopes below me. That said, the slopes below me also lacked consistent steepness and lose what little they have quickly - that was likely the bigger contributing factor. Either way, I wouldn't have skied any steep slopes facing an easterly (or northerly) direction today at any elevation. I didn't look at west or south-facing slopes on my tour.
Avalanche
I triggered multiple small avalanches on steep tailings piles with unsupported conex rollovers.