Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Tue
Alpine
4 · High
Treeline
4 · High
Below
4 · High
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Highlights

Widespread avalanches large enough to bury and kill you are expected at Snoqualmie Pass on Monday. This won’t be the day to try to tiptoe around the hazard. Stay well away from anywhere avalanches can start, run, or stop until these very dangerous conditions have subsided. 

Avalanche problems

  • Storm Slabs

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

    Until rain reaches upper elevations, snow will be the predominant precipitation type. With the intensity of snowfall we are expecting, dry natural avalanches should occur. As was noted above, it doesn’t really matter how you want to characterize these avalanche problems. The high precipitation rates, wind, and warming temperatures should be enough for you to realize that Monday will be a very dangerous day to be in the mountains. Even your usual “safe” areas down in the trees could be suspect due to larger avalanches running from above. Stay out from where avalanches can start, run or stop.

    (12/28/2021)

    The crown of a very large avalanche in the upper Chair Peak Basin earlier this winter. Dry avalanches like this could occur before a switch to rain or if the highest peaks stay cool. NE-E aspcet, 5800'. SS-N-R2-D2.5-U

    Photo: Dallas Glass

  • Wet Slabs

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

    Very heavy precipitation, rapidly warming temperatures, and strong winds will all combine Monday to create very dangerous conditions at the Pass. We expect lots of large natural avalanches big enough to kill you at all elevations. In some locations, these slides may entrain significant snow, break into older snow layers, and grow very large and destructive. Stay away from all avalanche terrain including where slides can run and stop. As temperatures creep ever higher, snow that maybe started the day as dry could quickly transition to wet as it is destabilized by heavy rain. While some of the resulting avalanches could be loose, many could be wet slabs or even glide. Truly it doesn’t matter, loose or slab, wet or storm; this isn’t a problem or day you want to play with. Keep away from all avalanche terrain until this storm plays out. 

    (1/9/2022)

    Gigantic debris pile from the very large (D4) avalanche on the West Face of Kendall Mountain earlier this year. We could be talking about similarly large avalanches from this cycle.

    Photo: Avalanche Professional

Avalanche Discussion

Starting Sunday night, we are expecting several rounds of natural avalanche activity by the time this storm has run its course on Tuesday. We should be in the storm’s bullseye on Monday, and we often talk about avalanches being more likely during periods of heavy precipitation or wind. Well, we are expecting significant snow at mid and upper elevations before quickly rising freezing levels allow the new snow to become soaked with heavy rain. The highest of peaks may be able to resist the warm temperatures to remain all snow for the duration of the event, but this is unlikely. These conditions will surely produce natural avalanches and we expect to see rounds of both dry and wet slides. We believe that all the snow above the Valentine’s Day Crust is in play to fail given the right terrain, so slides could grow very large and run toward valley bottoms. Many avalanche paths have filled in and been greased throughout the winter, giving potential slides the ability to run full path. This helps drive very dangerous avalanche conditions even at lower elevations.

Speaking of lower elevations, as if the storm and resulting avalanche danger weren’t enough; be aware of roof avalanches if you find yourself in an area with significant snow buildup on top of structures. The increasing temperature and rain should cause them to fall.

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