Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
Snowfall on Friday delivered 3 to 5 inches across the Selkirk and Cabinet Mountains, and 1 to 2 inches in the Bitterroots - Silver Valley. As a result, shallow wind-drifted slabs formed above a firm, slippery sliding surface on northwest to north through southeast-facing slopes. Slabs sitting above this hard and planar interface are particularly prone to avalanching. Throw in an additional 4 to 8 inches of new snow over the next 24 to 36 hours and these slabs will incrementally get deeper, potentially be more concerning, and extend below treeline into the middle elevation band.
Skier-triggered slides on Friday remained confined to the new snow, but traveled much faster down the slope than expected. If not paying attention to your surroundings in more complex or “no-fall” terrain, getting caught off guard could have a more dire consequence. Signs of freshly drifted slabs include surface cracking, wind etching, and lens-shaped pillowy snow. Manage your terrain to avoid areas below ridgelines and on steep convex rolls where your chances to trigger one of these drifts is elevated.
(3/28/2025)
Ski pressure on steeper slopes easily sheeted the new snow above the old, refrozen but breakable crusts. These were fairly predicatable and easy to manage, but traveled quick down the slope. Selkirk Mountains. March 28, 2025.
Photo: Chris Bilbrey