Lawinenlagebericht

Snoqualmie Pass

Northwest Avalanche Center
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Lawinengefahr

Tue
Hochgebirge
4 · Gross
Waldgrenze
3 · Erheblich
Unterhalb
3 · Erheblich
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Kernpunkte

Warming weather combined with heavy precipitation could cause large natural avalanches, especially at upper elevations Monday. Stay away from areas where avalanches can start, run, and stop. With so much recent snow, any avalanche could grow large and destructive

Lawinenprobleme

  • Storm Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Very Likely
    Größe
    2

    We’re now 6 days into a prolonged stormy period and yet another major system will impact the Snoqualmie Pass zone. Unlike recent storms, the heaviest precipitation, warmest temperatures, and highest winds should all converge during the morning hours potentially resulting in a natural avalanche cycle. If you travel up in elevation during the storm, stay out of all avalanche terrain. At mid and lower elevations, consider traveling around instead of through areas where larger avalanches could run and stop. With all the new snow on the ground, avalanches may entrain significant amounts of snow and become large and destructive. 

    Even if you don’t see natural avalanches, the up-side-down nature of this storm should create new weak layers that you can trigger on slopes greater than 35 degrees.  Use hand-pits and small slope tests to look for layers in the upper snowpack. You’re most likely to trigger layers in the recent storm snow above a prominent crust formed on New Years Day.

    (1/3/2021) Up track tests like this can highlight weak layers in the new snow. However, the only work as deep as your skis, snowshoes, or machine sinks into the snow. Other weak layers could hide deeper.

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2

    On Sunday more than a foot of snow fell at lower elevations around the Pass. Now with rising snow levels, we expect rain on this dry snow. You could see natural loose wet avalanches on very steep and rocky slopes below the rain-snow line. If you see new rollerballs or piles of wet debris, steer away from similar slopes. With all the new snow on the ground, some of these avalanches could become large and travel longer distances.

Avalanche Discussion

Snoqualmie Pass continues to experience a wild and wet week. Since 12/29 (the beginning of this storm cycle) the Pass received more than 8.5” of precipitation as of Sunday afternoon. This resulted in more than 50” of snow at 4300’. As storm totals continue to grow, so does our uncertainty. Several potential weak layers now exist in the upper snowpack that could fail and produce avalanches. If slides break into some of these deeper layers, very large and powerful avalanches could occur. Continue to exercise patience and let the snowpack adjust to all this new snow. 

Over this stormy period, cornices grew large and overhanging on many ridgelines. Reports from nearby zones showed them failing easily from the weight of a traveler. Give these tricky mountain hazards plenty of space. 

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources. Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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