Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

As this powerful storm slowly tapers off, dangerous avalanche conditions will linger. You could easily trigger an avalanche 2-4ft on Wednesday, especially at mid and upper elevations where powerful winds drifted snow into thick slabs. Avoid steep slopes and seek out terrain sheltered from the wind.

Avalanche problems

  • Storm Slabs

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

    Wednesday will be a much nicer day for the weather, but you can still easily trigger large avalanches. Storm slabs 1-2ft deep or wind slabs up to 4ft deep are possible throughout the terrain. You may even see a few natural avalanches. We expect the most potential for sensitive, very large avalanches on lee slopes at mid and upper elevations. With the extreme winds during this storm, even lower elevations could have thick wind slabs. You can avoid triggering one of these dangerous avalanches by choosing low-angle slopes sheltered from the wind.

    In some instances, avalanches could fail or step down into several deeper weak layers that extend back to mid-December. While we haven’t seen these types of slides at the Pass, they have occurred in other zones. These avalanches would be many feet deep and could wrap around terrain features.

    (12/20/2022)

    Example:  You could still trigger storm slabs of all sorts of shapes and sizes on Wednesday, including deep ones involving all the recent snow. 

    Photo: WSDOT Avalanche Team

Avalanche Discussion

What a wild storm! Snow totals are between 20-25in, and winds averaged in the 30mph range with gusts up to 70mph. A brief warmup overnight created a new freezing rain crust, but a quick return to snow buried this layer 20-30cm. It's still storming, and you can expect another 8-12 inches of snow overnight with continued winds. Snow and wind both taper off during the day on Wednesday. We have limited information about the extent of avalanche activity during this storm, but we expect it was widespread. There is some uncertainty regarding several weak layers in the upper snowpack  (Jan 4, Jan 2, 12/25, and Solstice Crust) that contain crust/facet combinations. Before this storm, snowpack test results were variable, but these layers failed and propagated in some. In other zones, these layers have been an ongoing concern. There's enough evidence to suggest any one of these weak layers could produce very large avalanches. They are now buried deeply, and until we can gather more information on their potential reactivity, extra caution and wide margins of safety are warranted. 

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