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Out of date — this forecast expired 4 years ago.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

Westerly winds and a few inches of new snow will drift snow into shallow slabs. You may be able to trigger small avalanches in this newly wind transported snow. Use caution in very steep terrain where even a small avalanche could push you over cliffs, rocks, or other obstacles. In adjacent zones, weak snow layers deep in the snowpack are producing large avalanches. Heed warning signs such as large whumphing collapses and gather information before committing to steep, open, alpine terrain. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Winds have shifted back westerly after a few days of blowing out of the east. A few inches of new snow and moderate winds may build shallow slabs of wind drifted snow. Look for actively blowing snow, small drifts, and observe the wind direction. We expect most of these avalanches to be small, but they could also take you for a ride through rocks or over a cliff.In East Central, large avalanches on deeply buried weak snow layers are occurring. I was out near Clover Flats yesterday, and while I could identify similar layers, I did not find these layers to be as touchy as conditions in East Central. However, this is our only data point, and other locations may harbor these deep instabilities. An avalanche on this layer could be quite large and run on the ground. Areas with blowing snow actively loading slopes may increase the pressure on these weak snow layers. Make sure to listen and feel for signs of instability, such as large collapses or shooting cracks. These are sure signs you should stick to low angle routes. Even without these loud signals of instability, it is worthwhile to dig down and identify any weak, sugary snow in the snowpack before committing to new steep terrain.

    (12/3/2022)

    Example of a small wind slab that you may encounter on Monday.

    Photo: Jamie Tackman

Avalanche Discussion

I was out enjoying some early season riding conditions near Darland Mountain on Friday. Grooming operations have yet to begin in Ahtanum State Forest, but travel on the roads was smooth. While coverage is much better, it's still early season, so expect rocks and bushes to be just under the surface. With so many things to hit, I did not venture far from established roads.

About 10 inches of snow exists at the trailhead, and the recent storm snow from 11/29 is the entirety of the snowpack until you travel above 5600ft. I found around 3 feet of snow at 6250ft in the sheltered terrain at Clover Flats. The upper snowpack consists of primarily low density storm snow. However, I did find a thin layer of small facets about 1.5ft down. It was unreactive in stability tests, but I could easily slide the column off on this layer smoothly in repeated tests, so it may prove to be a sliding surface for avalanches in steep terrain. The base of the snowpack is a mixed bag of strong crusts and increasingly dense snow. At the base of the snowpack, I identified weak, sugary snow. This is the same layer that is causing persistent slab problems in the East Central zone. At this site, the layering did not appear as much of a problem, but we're still suspect of higher elevation terrain especially facing northwest through northeast. 

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