Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 1–2
Yesterday, Southeasterly winds gusted over 20 miles per hour and peaked near 50 miles per hour over a 12-hour period. Expect to find fresh slabs of our recent snowfall in specific terrain today.
Be on the lookout for areas where the wind has built fresh drifts of new snow. Look for signs of wind loading, such as a scalloped or textured snow surface. It will be possible to find pillows, dunes, or other signs of thick, widespread wind slabs. Smooth, hollow-sounding or feeling snow and shooting cracks are signs you have found new snow instabilities. Avalanches may break wider than you expect in places where the wind has drifted and consolidated new snow into slabs.
You are most likely to trigger a wind slab as you climb in elevation below ridgelines in leeeward, steep, and convex-shaped terrain. Note that shifting winds will have cross-loaded gully features on multiple aspects. Although less likely, do not be surprised to find a soft slab in lower elevations on isolated terrain features such as steep drainage walls and open faces.
DRY LOOSE:
Expect to be able to kick off a dry loose sluff today. You could find loose snow at all elevations in steep terrain above 35 degrees where the wind has not affected new snow. These sluffs will not be large, but if triggered in areas where new snow has fallen on firm surfaces with continuity, they could catch you off guard and send you into hazardous terrain like rocks and drainages. Reduce consequences by managing your fall line and avoiding terrain traps.
Southeasterly winds in the 20s gusting near 50 miles per hour blew for 10+ hours yesterday--enough to transport new snow accumulated since Sunday.
Photo: Hatcher Pass Avalanche Center