Aspen

Avalanche

Jason Konigsberg, Mike Cooperstein · Feb 11, 2022 · Aspen

View on map

Weather

Windy near and above treeline on exposed ridges. Mild temperatures and mostly clear skies.

Snowpack

Loose Dry- Upper snowpack extremely weak below and near treeline. Once a loose dry avalanche starts and gouges down 30 cm it runs far, fast and full path if steep enough. Above treeline was mostly hammered by the wind so only isolated loose dry issues there.--- Wind Slab- The northwest winds were moving snow, mostly loading east and southeast-facing slopes near ridgetop. We did not observe any obvious signs of instbaility in regards to wind slab, but we also chose to avoid some steep terrain that looked wind worked. It seems that high in the start zones, it's hard slab sitting on hard slab, but once you descend to an elevation with recent loading and where near-surface facets were preserved, that is the sweet spot for triggering an avalanche. We did descend a moderately steep north-facing slope near ridgetop slope with only thin, unreactive wind slabs observed. We did not find a consistent slab over the newer weak layer, but again, we had to avoid the most suspect areas.----Snow depth (HS)- I would say the snowpack depth in this area is average and not a particularly weak and shallow area. HS ranged from 100 to 160 cm. Westerlys are the weakest and generally thin and faceted. Near treeline shady slopes held about 140 to 160 cm of total snow depth. We dug on a northeast-facing below treeline slope and found 130 cm of snow.----Overall snowpack impression- On most slopes, the slab from December is still up to pencil hard and extremely hard to effect. I am not really spending the time to test the basal layers with ECTs anymore. The faceted layer above the depth hoar is still 4-finger hard, so it hasn't gained a ton of strength, but it will take a big load to effect it. Best guess would be 3+ inches of SWE.

Avalanche

We intentionally triggered a few small loose dry avalanches with one larger one that ran to the valley bottom, fanning out, and depositing significant debris in the creek.