Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Unlikely
- Size
- 1–1.5
What and where is it: About 2 inches of recent snow, transported by strong west to northwest winds, has formed small wind slabs in steep east-facing lee terrain. Yesterday’s field observations showed a mix of wind-scoured surfaces with isolated drifts confined to wind-protected terrain features (OBS1, OBS2, OBS3). Where slabs exist, they are generally small and limited in extent, and have been stubborn to unreactive with limited signs of instability observed. They are most commonly found at mid elevations in sheltered gullies, below rollovers, and behind terrain features that collect drifting snow. The Summer Lion Head Trail is one example of where these drifts can form. How can you recognize it: Wind slabs typically have a smooth, rounded, or pillowy surface that contrasts sharply with the textured, refrozen, wind-scoured snow. With good visibility, these differences are often easy to spot.
How can you manage it: Manage this problem by avoiding smooth, wind-drifted snow on steep slopes. Most slabs in avalanche paths are expected to be shallow, but depth can vary in sheltered pockets. If you find a slab deeper than boot-top, stop and assess how big it is, how continuous it is, and what’s below it, as it may be more consequential.