Persistent Slabs
- Hochgebirge
- Waldgrenze
- Unterhalb der Waldgrenze
- Wahrscheinlichkeit
- Possible
- Größe
- 2–2.5
Slabs that formed in early February rest above a variety of ugly, widespread, weak layers (facets, surface hoar, crusts, and combinations). Before triggering an avalanche, you're unlikely to 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:
- The snowpack is less than about 4 feet thick—relatively shallower spots may exist where the wind frequently blows, and the slab is not uniformly thick.
- 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
- A smaller wind slab or loose snow avalanche overloads the buried weak layers
(2/18/2025) A skier on Patterson Pk near Hailey triggered this large avalanche. After several turns on the slope, the slide broke above and around them. Thankfully, the skier was able to ski ahead and to the side of the slab. NW @ 8,050'. Photo: Sawtooth Avalanche Center