Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 2–3
Evidence of instability on a variety of weak layers and large natural avalanches continues to be reported daily. Recent wind and precipitation incrementally added depth and weight to a hard slab sitting 1 to 5 feet above weak layers. A supportable crust exists on all aspects and elevations up to about 6,500 feet. Expect this crust to thin and/or disappear as you gain elevation, above there recent wind-transported snow will take over the additional loading.
Don’t let the fact that you’re on a supportable crust lure you onto a suspect slope. The weak snowpack structure should guide your travel plans. Steep slopes that face NW-N-S are still to be avoided. Find safer, better-riding conditions where the wind has less effect, and the slope angle is gentle.
Snowpit test scores continue to show sensitivity within several weak layers.
(3/9/2026) Northern Swan, 6500', N aspect Both of the persistent buried surface hoar layers failed in stability tests. mid-Feb, ECTP15 JDL, ECTP19 Photo: chris gotschalk