Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
You can find buried weak layers 1-3 feet down that show some signs of healing, but we can't say for sure with much confidence, given the lack of data. Instead, focus on wind and warmth maintaining the likelihood of this problem. The most likely place you'd trigger a slide is in exposed wind-loaded terrain, and weak layers can be buried even deeper here, too. Recent very small wind slabs could be lingering in these areas as well, but only immediately adjacent to the Cascade Crest. By the afternoon, a bit of rain along the Crest could reach middle elevation terrain. It's unlikely, but if water works its way down to buried weak layers, this could reinvigorate instability by the end of the day.
We have very limited data for the zone, which creates sizeable uncertainty around an already tricky problem to manage in the backcountry. If you plan to travel near a neighboring forecast zone, consider reading that forecast as well to equip your toolbelt with more information. Either way, ease into terrain slowly. You may or may not get clear feedback from the snowpack before triggering a large slide.
(3/1/2026)
Snow machine triggered large (D2) persistent slab and self extricated on 2/28. Darland Mt. NE aspect, 6700 ft.
HS- AMu-R2-D2-O @ NE, 6700' Photo: Northwest Avalanche Center