Avalanche forecast

East Slopes South

Northwest Avalanche Center
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Avalanche danger

Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

A significant storm will bring snow, wind, and quickly increasing avalanche danger. You can easily trigger avalanches in the new snow on steep slopes, particularly at upper elevations where winds deposit snow into deep drifts. Keep slope angles low and choose conservative terrain while this storm impacts the Cascades.

Avalanche problems

  • Storm Slabs

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

    A welcome return to wintery weather will increase the likelihood of triggering avalanches. We anticipate a bump in freezing levels and high precipitation rates to form widespread sensitive storm slabs. These avalanches may run on slick crusts at lower elevations or weak surfaces in higher elevation northern terrain. Look for red flag signs of instability, such as recent avalanches, cracks shooting away from your equipment, or collapsing of the snow beneath you. You can use small, inconsequential test slopes and quick hand pits to observe how the new snow reacts. If new snow slides easily, that's a sign that avalanches are likely on steep slopes. It will be a good day to stick to simple terrain and enjoy low angle skiing or riding in the fresh snow. At upper elevations in exposed locations, winds will form deep drifts of snow on lee aspects, and larger sensitive winds slabs may develop. Tuesday isn't a day to travel into wind-exposed terrain. Stick to forested areas, sheltered from these strong winds. The bump in temperatures won't be the first warm up that lower elevations have experienced. Still, new snow overnight with warming afternoon temperatures may make wet loose avalanches possible below 4000ft. So look for signs such as rollerballs and pinwheels to indicate these wet avalanches are possible. 

    (12/20/2022) 

    Small test slopes like this that produce mini avalanches are a red flag sign of instability. 

    Photo: Josh Hirshberg

Avalanche Discussion

A few storms over the last month have brought minor refreshes, but this will be the first major storm to impact the East South since the warm, wet MLK storm. While it will surely be a nice change back to deep powder riding and skiing, the snowpack will need time to adjust to this new load. So allow the storm to move through and new snow instabilities to settle before considering steeper terrain. The winds will be a significant factor in this storm, and these stiff wind slabs will take even longer to heal, particularly in alpine terrain, where they may have formed over weak snow surfaces on northern aspects. While generally, the snowpack in the East South is strong, we identified some weak faceting snow over the MLK crust in Ahatanum Meadows. While we don't anticipate this storm to awaken this persistent weak layer, there is always some uncertainty, so conservative terrain choices are critical until we see how the storm plays out. We expect most avalanche concerns to be limited to the new or recent snow.If you get out into the East-South, please let us know by submitting an observation!

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