Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 1.5–2.5
Well documented weak layers exist in the upper snowpack on all aspects. However, most of the avalanche activity seems to be isolated to wind loaded areas. With significant winds in the forecast for Thursday, we expect that trend to continue.
Sure, you may trigger a small fresh wind loaded pocket, but the real issue is slabs failing on deeper, older, weak layers. Don’t try to treat these like normal wind slabs. They could break widely, trigger after several people have traveled the slope, or fail above you. Give wind loaded terrain a wide berth.
While we expect the bulk of the persistent slab issue to be confined to wind affected slopes, other zones have certainly proven these layers can rear their head at surprising times and in surprising ways. Simple, planar, and lower consequence terrain can stack the odds in your favor in case this problem expands. If you see any common red flag signs of unstable snow, dial it back and steer clear of all steep open slopes.
(2/28/2026)
A widely propagating natural avalanche below Cutthroat Peak. This avalanche is suspected to have failed on weak snow over the 2/7 crust. 7000ft, S-SW aspectN-R4-D2.5-O
Photo: NCH