Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
Around 3" of snow fell around Washington Pass with 0.16" of water equivalent on Monday night; significantly less or no snow fell at lower elevations east of the Pass. E Winds ramped up into the strong range (34 mph, gusting 50). Information in this zone is limited right now, but we suspect that winds drifted fresh snow and pre-existing dry snow on shaded aspects to form generally small, reactive slabs near and above treeline. We expect isolated large slabs at upper elevations near ridgelines. Slabs formed on atypical aspects focusing on the W half of the dial. Winds likely stripped E-facing aspects down to crusts or old snow interfaces. Sharp, fresh cornices above atypical aspects may alternate with older larger cornices that have built up above N and W-facing aspects most of the season. The slopes below these fresher cornices were recently wind loaded and may still be reactive. Cracking snow surfaces, punchy snow, or settlement as you travel also provide warning signs that you're entering wind-loaded areas. Use your pole or a probe to assess the depth of recent snow above a crust or old snow interface. Become increasingly alert as you find higher average amounts. And if the depth increases locally, you're in a wind-loaded location. Wind slabs will be more stubborn by Wednesday, but you could still trigger one. Steer around wind-loaded slopes steeper than 35 degrees where you expect drifts 6" or deeper and choose more conservative terrain if you're finding more widespread signs of instability including recent avalanches.
Example: If you start seeing signs such as cracking and little wind-drifted slabs sliding out - shift to a more conservative plan and steer around wind-loaded slopes.
Photo: Josh Hirshberg
