Persistent Slabs
- Alta quota
- Limite del bosco
- Sotto il limite del bosco
- Probabilità
- Unlikely
- Dimensione
- 1.5–2.5
Weak layers buried 1 to 3 feet deep caused a rash of human-triggered and natural avalanches over 10 days ago. Most avalanches that occurred on these layers were large enough to bury a person. Some were destructive enough to break mature trees.
You are least likely to trigger an avalanche in low-angle terrain or on slopes with a strong and supportable surface crust. This crust will be thinner, weaker, or non-existent on shaded slopes above 6500'. Consider moving to lower-angled slopes anywhere you or your machine start to punch deeper into the snowpack.
You might not observe obvious signs of instability before triggering a slide. Avalanches can break well above you and propagate widely. Favor slopes where an unexpected slide won't carry you through rocks and trees, push you over a cliff, or bury you deeply in a gully.
(1/15/2026)
This large avalanche likely failed on a buried weak layer at 7,400 feet on a NE Aspect. This avalanche occurred naturally and sometime earlier in the week (1/10-1/13).
Photo: Guy Zoellner