Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 1.5–2
Yesterday (Saturday), a large avalanche occurred in the southern Whitefish Range, and shooting cracks and collapses were observed between WMR and Stryker Ridge. A widespread, well-preserved layer of surface hoar, found 1-2 feet below the surface, was most likely responsible for the activity. Additional snow and wind overnight have stiffened the surface and will keep the chance of a human-triggered slide likely today.
The danger is greatest in terrain facing NW-N-NE-SE, where there is no supportable crust to limit your impact on the weak layer. As you gain elevation, and especially on wind-loaded slopes, the resulting slides will increase in size and be capable of injuring or burying a rider.
In areas favored by recent snowfall or wind loading, storm or wind slab avalanches may trigger larger slides on the buried weak layer.
Look and listen for signs of instability, such as cracking and collapsing (whumpfing), which indicate you have found a sensitive slab. Recent avalanche activity is bullseye data that the snowpack is unstable.
Avoidance is the best mitigation for this pesky problem. Sunny slopes with a supportable crust beneath the new snow will allow for the safest travel. Stick to low-angle terrain that is not connected to steep overhead hazards if you plan on recreating on the north side of the compass.
(2/14/2026)
This avalanche likely failed on Saturday (2/14) at a buried weak layer. It is unknown whether this slide failed naturally or was triggered by a rider. This occurred on a mid-elevation south-east aspect.