Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
As long as temperatures remain cold enough that Friday's precipitation comes as snow and not rain, we can expect to find wind slabs at near-treeline and above-treeline elevations. Sustained westerly winds (gusting into the 20 mph range) mean that you'll most likely find wind slabs on east-facing aspects, while north and south aspects could be cross loaded.
Ahead of this new snow, snow surfaces vary widely across the Central Cascades. On Thursday, there were observations of surface hoar. If new snow gets deposited on top of intact surface hoar, wind slabs have the potential to propagate farther than you might expect. Additionally, while 2-4 inches is not a significant amount of snowfall, remember that areas of wind deposition can hold 3-5 times more snow than what accumulates in sheltered terrain.
Look for plumes of snow and wind drifts near ridgelines, and a snow surface that's rippled or smooth and firm on lee aspects. These are signs of wind transported snow and may indicate the presence of a wind slab, particularly in open areas near and below ridges. If you observe signs of wind slab instabilities or snow deposits that are deeper than expected, back off to sheltered slopes below treeline. Keep in mind, riding low angle terrain is another good way to avoid the avalanche problem while finding the best turns in "dust on crust" conditions.