Avalanche forecast

East Slopes South

Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Precipitation will taper off on Sunday, but continued warming will sustain dangerous avalanche conditions. You could trigger very large wet avalanches on deeply buried weak layers. These avalanches are hard to predict and can be incredibly destructive. Keep your travel plans conservative by sticking to low-angle slopes and staying well out from under large open slopes. 

Avalanche problems

  • Wet Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–3

    Avoid traveling on or near large, steep terrain features. Give yourself large margins of safety from potential runout zones. One of these wet slab avalanches could run further and break wider than you may expect. A good strategy is patience and conservative terrain selection. If you experience whumphing collapses, use extra caution to avoid steep terrain. However, you may not get warning signs before triggering an avalanche. Wet slab avalanches are notoriously unpredictable. They often lag behind peak precipitation and can fail unexpectedly even after rainfall has ended. Weak, faceted snow over the Solstice Crust is the culprit in most of these very large avalanches. With more rain and continued warming, liquid water impacts these weak layers within the snowpack, resulting in wet, heavy, and destructive slab avalanches. Crystal Mountain reported a very large wet slab avalanche on Saturday. We expect these avalanches occured in the East South on Saturday as well, and we'll likely see more with the wet and warm weather forecast. Smaller and more predictable wet loose avalanches may also be widespread on Sunday. While these are likely to be less harmful by themselves, they have the potential to step down and trigger one of these much larger wet slabs. 

    (1/27/2024)

    In nearby West South zone, this large natural wet slab failed about 3ft deep on Saturday (1/27) afternoon. N, 6800ft, WS-N-D2..5-R2-O

    Photo: Crystal Mt Ski Patrol

Avalanche Discussion

Another .5" of water overnight is possible for East South, and snow levels will steadily climb up to 9000ft by Sunday evening. In nearby West South, multiple very large wet slabs ran naturally at Crystal Mountain, Mt. Rainier, and Mt. St. Helens. We have some uncertainty about the timing of peak instability for the East South. A natural avalanche cycle likely occurred on Saturday in East South as well, but we have limited observations. There was less overall precipitation on the east slopes, so natural wet slab avalanches could run during the overnight hours or even into Sunday. Even as natural avalanche activity tapers off, you could still trigger one of these nasty avalanches. With scary, hard-to-predict wet avalanches, the take-home point is that until the snowpack experiences below-freezing temperatures, the potential for very large wet slabs remains. Consider the consequences of overhead hazard or triggering one of these deadly avalanches when choosing terrain. 

On Friday, an NWAC forecaster was out in Ahtanum Meadows near Darland mountain and found the Solstice crust buried over 3ft deep and the 1/2 surface hoar buried 2-3ft deep in a snow profile. While both layers were gaining strength and rounding, the rain and warming will eventually be the tipping point for avalanches, even on these western edges with a deeper overall snowpack. Further east and north, near Manastash ridge, these layers are closer to the surface. They could be much easier to trigger or potentially already saw a round of natural avalanches on Saturday. They also found a notably stronger snowpack on southerly aspects versus northerly and easterly.

If you get out, let us know what you see by submitting a public observation!

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