Avalanche forecast

East Slopes South

Northwest Avalanche Center
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Avalanche danger

Tue
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

You can trigger an avalanche in wind drifted snow on Monday. Avoid steep wind-exposed slopes if you notice active drifting or see signs of unstable snow such as shooting cracks.

Avalanche problems

  • Wind Slabs

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

    A few more inches of snowfall paired with a good dose of moderate wind speeds will help wind slabs grow in depth and distribution across the terrain.  These slabs may be more toucy in areas where they are forming over a slick crust or weak snow on more northerly slopes. As we move into the morning hours, winds will switch more easterly, so look for slabs forming in atypical locations and cross-loading terrain features. Nothing good ever comes out of upslope winds, so keep an eye out for slabs forming in some not so common spots. 

    The good news is that you can use visual clues to help you identify slopes of concern. Look for blowing snow, cornice growth, ripples, or rounded pillows at the snow surface to identify where the wind has been at work. If you see shooting cracks under your skis/sled or feel wind-stiffened snow, be ready to take a big step back and avoid nearby steep slopes. 

    (1/10/2023)

    Blowing snow and sharp drifts along a ridgeline can help you anticipate wind-loaded features. 

    Photo: Andy Harrington

  • Loose Dry

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

    New low density snow will certainly be moving on steep terrain features once a trigger is added. Look for these dry sloughs on steep rollovers near and above treeline. With this avalanche problem, consider run-outs and possible parties below. These sloughs are often more manageable, however they could create problems if paired with a terrain trap or other groups traveling below.  Have a plan before skiing into steeper rolls and make sure the run out is clean. 

    (2/22/2023)

    An example of small dry loose sloughs 

    Photo: Katie Warren

Avalanche Discussion

On Sunday, the East South snotel sites picked up 1-3 inches of new snow. You may find higher amounts on the western edges of the zone if you travel closer to the Cascade Crest. New snow is falling on a variety of surfaces. On American Ridge, I was finding near-surface facets and isolated surface hoar on shaded aspects. On more solar aspects, new snow is falling on a thin sun crust formed on 2/25.  Check out my observation here. Your key will be to assess how the new snow is bonding with these old snow surfaces. 

The East South has gotten a few observations this past week! One observer reported triggering wind slab near ridgetop on Darland Mtn on Saturday ( observation). Another observer reported blowing snow and signs of wind slabs on Quartz Mt.  NWAC Forecaster Dallas Glass traveled in the near the western part of the zone and found lots of wind affected snow and weak surfaces. 

Thanks for the great observations! Avalanche forecasting is a community project, so if you get out let us know what you see by submitting an observation!

 

 

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