Persistent Slabs
- Alta quota
- Limite del bosco
- Sotto il limite del bosco
- Probabilità
- Possible
- Dimensione
- 2–2.5
Although the slabs that formed in early February seem to be stabilizing, they rest above a variety of ugly, widespread, weak layers (facets, surface hoar, crusts, and combinations). Before triggering an avalanche, you may or may not experience obvious signs of instability like snowpack cracking and collapsing or whumpfing. Persistent Slabs can release in surprising ways and break much wider than expected. You are most likely to trigger a dense, 2-4 foot thick avalanche where:
- A smaller wind slab or loose snow avalanche overloads the buried weak layers (problem below)
- Any part of the slope you are on or connected to is steeper than about 35 degrees
- The slope faces the northern 2/3 of the compass
- The slab is less than about 3' thick—relatively shallower spots may exist where the wind frequently blows, and the slab is not uniformly thick.
(2/17/2025) Sun Mountain E avalanche looking up from the bottom of the debris
Photo: Sawtooth Avalanche Center