Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 1–2
With new snow and wind, we could begin to see avalanche activity increase on buried weak layers. This isn't a powerful storm, so we have a fair amount of uncertainty if reactivity of the persistent slab will increase. That said, both small, fresh wind slabs and deeper persistent slabs are in the cards in wind-loaded terrain. Upper elevations and areas near the Cascade Crest will be the places where avalanches are easiest to trigger. Avoid steep slopes below corniced ridgelines and areas with stiff, wind-textured surfaces. Current reports indicate most avalanches have been small, but with limited access to the zone, we have considerable uncertainty. And even small avalanches can carry high consequences in the wrong terrain. So it's important to step into terrain slowly, choosing moderate, sheltered, small slopes. Persistent weak layers can be tough to assess as you travel, so the best mitigation tool you have is terrain avoidance.
(3/1/2026)
Snow machine triggered persistent slab avalanche in the neighboring East South zone on 2/28. [HS- AMu-R2-D2-O @ NE, 6700']
Photo: Joe Dellaporta