Avalanche forecast

East Slopes Central

Northwest Avalanche Center
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Avalanche danger

Sun
Alpine
1 · Low
Treeline
1 · Low
Below
1 · Low
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Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

In the majority of the zone, avalanches are unlikely. However, Low danger doesn't mean "no danger." Considerations to keep in mind are old weak layers of snow and shallow coverage in the Wenatchee Mountains, wind drifted snow at upper elevations, and wet, weak snow below treeline.

Avalanche problems

  • Wind Slabs

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

    At upper elevations, slabs formed during strong southwest winds on the 12-13th at the tail end of a major storm. Cornices grew during the storm and may still loom over slopes. Triggering a wind slab avalanche is now unlikely, but still worth keeping in mind. Pay attention as you transition into wind affected terrain, and look and feel for changes in snow surface texture and hardness. Watch for clues of instability like cracks shooting through the snow. Use caution on slopes with similar features where you see overhanging cornices and wind drifts. Minimize exposure to overhead hazards and stay off of cornices. 

    In addition to slabs on the surface, deeper weak layers exist above 5,000ft in areas with a shallow snowpack, such as the Wenatchee Mountains. While it seems unlikely that you could trigger a persistent slab avalanche, we still have uncertainty at the highest elevations. If you are in areas with less than 4 feet of snow on the ground, be prepared to make your own assessment of the snowpack.

    Example of intense wind loading off a ridgeline.

Avalanche Discussion

Although wet avalanches are unlikely, you may find wet unsupportive snow, especially in open terrain at low elevations and in the southern and western portion of the zone. If you sink into wet snow up to your boot-tops, you may be in an area with conditions for wet avalanches. You can avoid triggering a slide by moving onto firm supportive snow or sticking to lower angle (less than 35 degrees) terrain. 

Deeper weak layers exist in areas with a shallow snowpack, such as the Wenatchee Mountains. On Thursday, I traveled south of Blewett Pass and found about 2.5-4 feet of snow on the ground with a number of hard crusts over weaker faceted snow from December. Snowpack tests pointed to the potential for triggering avalanches that could propagate widely on the December facets. That said, the overlying stout crusts made triggering avalanches on this weak layer seem unlikely. 

From January 11th to 13th a major storm hit the region. Large and destructive avalanches ran on the 12th, both as storm slabs and later wet avalanches. Observations were been limited but in adjacent zones the activity was well documented. I was on Stevens Pass, on Tuesday and every avalanche path I could see had at least one, if not multiple avalanches in it. On Washington Pass, observers reported avalanches up to D3 in size (big enough to break mature timber and bury cars) including an avalanche that hit a closed portion of Highway 20, below Delancey Ridge. 

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources. Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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