Avalanche forecast

Stevens Pass

Northwest Avalanche Center
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Avalanche danger

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

We won't get much rain, but the weather is staying warm, and water is saturating further into the snowpack. The warm trend is maintaining dangerous avalanche conditions. Avoid travel on or below big, steep slopes, cornices, cliffs, and rocky terrain covered in snow.

Avalanche problems

  • Wet Slabs

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

    Well-above-normal temperatures and a weak snowpack structure ask for continued caution. Wet avalanche likelihood may decrease slightly as the days go on, but a lot of uncertainty exists with deeper layers being impacted by percolating water as it travels deeper. If you do trigger an avalanche, even if it's a small one, there's a chance it could step down to a deeper layer, becoming large and powerful with thick, wet, and chunky debris. Large or very large natural avalanches aren't out of the question, as we're in a shedding cycle right now.

    The easiest solution will be to skip travel on or under steep slopes until the snowpack has a chance to stabilize and temperatures trend more seasonal. Even if avoiding travel on steep slopes, the best policy would be to also pay close attention to what is above you.  Stay out from under cornices that could fall and trigger a large avalanche on the slope below. Glide cracks indicate where the entire snowpack is slipping and could fail on the smooth ground underneath it.

    Example photo: One of those unpredictable, tricky, wet slab avalanches failing on weak grains near a crust, which may be similar to what we might see on Tuesday. 

Avalanche Discussion

Steven's Pass isn't forecasted to get much rain Monday night and Tuesday, probably totaling less than a tenth of an inch. Even so, we'll remain overcast and temperatures will reach almost as high as Monday, with freezing levels around 7000ft. This means we'll still have a melting snowpack with water saturating deeper. I ski toured in the Lake Valhalla area on Sunday and when I stepped out of my skis I mainly only sank in knee deep, although in some spots we sunk further. The snowpack was much less supportable on Monday, with boot penetration reported as up to the thighs or deeper, making travel very challenging and adding a lot of uncertainty about failures in the snowpack. 

Most avalanche activity seemed to happen at the end of last week and over the weekend with the initial warming.  Many wet loose and slab avalanches up to D2 were reported. Avalanche control work at Stevens Pass Ski Area over the weekend produced a couple of avalanches that broke into older, deeper layers that have been lingering in the snowpack since late December. Regionally, very large slides have occurred on a similar old weak layer at Mission Ridge on Wednesday and Crystal Mountain a week ago. This crust/facet complex is now 4-5 feet below the surface in much of the zone. Last week, observers reported sudden and propagating test results on this weak layer. If you venture to the eastern half of the zone, it would be worth reading the East Central forecast. If you make it out, please share what you found with an observation.

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