Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
What and where is it? You may be able to trigger 1-3 foot thick slabs in wind-loaded terrain near and above about 8500'. Some slabs overlie crusts and/or thin layers of weak, faceted snow; the slabs could break wider than expected. Triggering these large avalanches is most likely on "prime time" slopes angles for slab avalanches—slopes approaching or exceeding about 40 degrees.
How can we recognize and manage this problem? The wind slabs are fairly easy to spot and avoid. Watch for smooth pillows below ridgelines and cornices as well as on the sides of cross-loaded gullies. In the craggy Sawtooth Mtns, slabs commonly form in cirques below large cliff faces and on the aprons of large chutes and couloirs. Dunes and ripples on the surface are clues the wind has been at work transporting snow, and cornices falling are great triggers for the wind slabs below them. If you feel the snow surface getting stiffer, it's time to pay attention. Cracks shooting out from your skis or sled are an obvious sign that you've found a wind slab. Hard wind slabs sound hollow, like a drum, and behave unpredictably; they can break above you and wider than expected.