Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1.5–2.5
Weak snow that formed in November sits near the base of the snowpack in the majority of terrain above 8,500’. Loading from the last ten days of snowfall and strong wind have stressed these weak layers making them sensitive to human triggers. A snowmobiler triggered a 3-4 foot deep avalanche involving weak snow from November three days ago. Triggering a persistent slab avalanche is most likely in very steep terrain that faces east through north.
Sidehilling in trees triggered the avalanche. No one was caught or injured. This avalanche occurred 12/26.
Photo: John Sievers