Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1
Firm sun crusts on many windward slopes and moderate wind speeds limited wind slab formation to the most wind-exposed NW-N-NE-E aspects in near and above treeline terrain. In some cases, these wind slabs formed on top of weak feathery snow known as surface hoar. Some wind transport and wind-loading could continue today in isolated areas particularly if any new snow accumulates. Most avalanches resulting from these wind slabs should remain small. Small avalanches can have serious consequences especially with all the rocks and obstacles lurking near the snow surface. It is not impossible for a wind slab avalanche to involve enough snow to bury or injure a person (size D2) in some areas.
Signs that wind slabs may exist on a slope include cornices above a slope, wind drifts/pillows, ripples/wind-created textures on the snow surface, hollow sounding firm snow, and current blowing snow. The buried surface hoar will make any wind slabs that do exist more difficult to manage. Surface hoar can allow remote triggering of avalanches and can allow avalanches to propagate across wider areas and run farther downslope. If there are any doubts or uncertainty about the existence of an unstable wind slab on a slope, assume the slope is unstable and avoid it. Avoiding wind-loaded terrain where problematic wind slabs may linger represents a great way to manage today's potential avalanche problem and to enjoy the cold soft snow that still remains in many more-sheltered, non-wind-exposed areas.