Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
Southwest winds increased yesterday afternoon and transported snow above 6500'. Look for fresh slabs of wind-drifted snow on slopes facing (NW-N-NE-E- SE). Older slabs were deposited on very weak snow, ranging from soft to hard, and can break 1 to 2 feet deep. These slabs might propagate far wider than expected or well above you. You can find these on all aspects due to shifting wind directions during the last week and in isolated pockets below 6500'.
Look for signs of wind-affected snow (like an etched surface or dune-shaped features) along ridges, saddles, and in open bowls. Cracking around your feet or machine is a sign of unstable snow, and a good reason to find a slope that is less steep or more sheltered from the wind. Hard slabs can support your weight and may not give signs of instability until it is too late.
An observation from the Flathead Range noted gusty winds blowing in all directions. They noted cracking and triggered a small soft slab on steep wind-affected slopes.
(2/1/2025)
Textured surfaces mean it is possible you will encounter unstable slabs of wind drifted snow. You are most likely to find these along ridges and saddles, or in open bowls or gullies.
Photo: Flathead Avalanche Center