Persistent Slabs
- Hochgebirge
- Waldgrenze
- Unterhalb der Waldgrenze
- Wahrscheinlichkeit
- Possible
- Größe
- 1.5–2.5
Recent Avalanches: It has been about two weeks since the last known avalanche activity on buried weak layers in Summit Lake. Since then, we have seen mostly glide avalanche activity.
The warm and wet weather last week didn't do any favors for the skiing and riding conditions, creating an icy crust up to about 2600'. However, now that the snowpack has refrozen, the silver lining is that the wet weather added some strength to the snowpack. So we an not as concerned about buried weak layers at treeline elevations and below.
Above 2500', we are still concerned about several weak layers of buried surface hoar that range from 1 to 3' deep in the snowpack and have the potential to cause large human-triggered avalanches. Buried surface hoar is notorious for giving no signs of instability (no red flags) and remaining dangerous for a long time, which makes it very difficult to assess and manage. One public observation from this weekend shows that these weak layers are still concerning in the Summit Lake area. To avoid the potential for being involved with one of these avalanches, you can always stick to simple, low angle terrain and avoid travelling above terrain traps like gullies, trees, or cliffs.
(12/6/2025)
Snowpit test showing failures on two buried weak layers in the upper snowpack.
From: Bennett, Richard, Gus, and Ben