Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 2
Weak, rotten snow from November is buried by a slab of heavy, dense storm snow up to 2 feet deep. Where sugary snow from November existed before last weekend's storm—on north-facing slopes at mid-elevations (7500-8500 feet), and on all slopes at upper elevations —there is potential to trigger dangerous, widely propagating avalanches. In these conditions, avalanches might be triggered remotely from below or from a distance.
- Slab avalanches failing on the buried persistent weak layer are most likely in areas where the wind has drifted snow, near ridgelines, and mid-slope catchment areas like gullies.
- Even a small avalanche could be dangerous in these shallow snow conditions, as you might be dragged through the rocks or down trees below.
- Follow safe travel protocols: travel with a partner, cross (or ride) steep slopes one person at a time while the rest of your party watches from a safer place.
December 7, 2025: Buried Persistent Weak Layer—An Obvious Problem!