Avalanche forecast

East Slopes South

Northwest Avalanche Center
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Avalanche danger

Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

With moderate winds and a little fresh snow, you could trigger avalanches in shallow slabs of wind drifted snow. Ridges and the base of cliffs are the most suspect terrain features. Steer around these stiff pillow like drifts on steep slopes.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    A few inches of fresh snow fell last night, and winds quickly drifted this snow around into shallow, sensitive wind slabs. These shallow fresh wind slabs rest over slick melt-freeze crusts, potentially making them sensitive to triggers. Probable locations to trigger these avalanches are near ridges, the base of cliffs/rocks, or convex rolls in terrain. You can recognize wind slabs by their pillow-like form and potentially hollow sound. A dusting of new snow may have obscure textured surfaces, so instead, look for cornice formations and drifts behind trees and rocks to identify likely wind slab locations. You can also use your probe or pole to feel for stiffer layers over softer layers. Any shooting cracks or collapsing is a sign to avoid steep terrain. 

    (1/4/2023)

    A very shallow wind pocket failed. Notice the textured surface and how it looks "fat" compared to the surrounding terrain.

    Photo: Dallas Glass

Avalanche Discussion

Low-elevation trailheads below 3500ft may continue to see precipitation in the liquid form, making wet loose avalanches possible. Avoid steep terrain where you are sinking deeply into wet, heavy snow, and be cautious of traveling below steep rocks and cliffs. 

We are at the tail end of a widespread natural avalanche cycle. Many locations saw very large wet avalanches running long distances and impacting low elevation terrain. WSDOT NCR avalanche crew reported multiple D2 wet slab avalanches, with a couple up to size D3. The snowpack is draining water, temperatures are cooling, and the main event seems to be behind us. We are just beginning to get a handle on the extent of this avalanche cycle and the current state of the snowpack. The snowpack likely looks significantly different than before this storm, and an NWAC forecaster noted rocks emerging on steep south-facing slopes on Saturday. So be prepared for challenging travel off trail at lower elevations. Breakable crusts, wet snow, open creeks, and other obstacles are other hazards that may keep you on your toes if you are out enjoying the holiday.

Last week, I traveled into the Soup Creek area. Most notably, I found deep pockets of wind-drifted snow and observed active wind transport along ridgelines. In some places, up to 3 feet of snow rests over the Christmas Crust. I traveled on multiple aspects and elevations around this zone and was able to locate buried surface hoar in sheltered areas on northerly aspects in meadows and sparsely treed slopes. Rain probably destroyed this weak layer at low and mid elevations. But precipitation likely remained as snow above 6000ft, potentially preserving this weak snow layer. So as you get out to enjoy the new snow, assess snowpack conditions as you travel. Use test slopes to monitor how the new snow bonds with underlying surfaces and heed warning signs such as shooting cracks, recent avalanches, and collapsing.

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