Aspen
AvalancheBrian Lazar · Nov 29, 2022 · Aspen
Weather
Cold, with a moderate westerly winds below treeline. Much breezier in the alpine as observed from a distance during brief windows of visibility. Light snow through morning with some periods of S2 around 11AM. Around 4 to 5 inches of additional accumulation during the day.
Snowpack
Very tender and dangerous snowpack conditions. The very weak 15cm-thick layer of near surface facets is the reactive weak layer of concern. Last weekend's storm drifted into a thin, and stiff wind skin that now sits below the new 35-40 cm of storm snow. There are thicker drifts at higher elevations. This makes slabs 2 to 3 feet thick very easy to trigger. We experienced shooting cracks up to 100 feet long nearly every step or turn into fresh snow, and more isolated large collapses. The storm snow if F hard at the surface, and transitions to 4F hard just above the 1F-hard wind skin. Expect avalanches to grow in size and connect terrain features as the slabs settles over the next 36 to 48 hours. On the positive side, the basal facets are showing signs of strengthening and are not as big a concern at the now mid-pack near surface facets.
Avalanche
Limited visibility obscured most natural avalanche activity, but we did see a couple natural D1 soft slabs below treeline on east and north-east facing slopes. Couldn't really see into the alpine, but suspect many more ran. Remotely triggered two D1 avalanches remotely from the ridge into north-facing terrain. A group near us remotely triggered a D2 avalanche on an east-facing slope around 11,000 feet. The avalanche was triggered from around 150 feet away, broke a few hundred feet wide and then sympathetically released a D1 avalanche about 50 feet further south. The debris ran around 500 vertical feet. This is good evidence we are squarely into D2 size category, and this size avalanche is now pushing into below treeline terrain. Dangerous conditions limited travel into higher elevations, but suspect these avalanches are just a glimpse into the scale of activity.