Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

High elevation rain could drive another round of wet avalanches at Snoqualmie Pass on Thursday. Limit the amount of time you spend under steep rocky slopes and keep in mind that instability could linger even after the rain has stopped.

Avalanche problems

  • Glide Cracks

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2

    Another round of wet and warm weather is on its way to Snoqualmie Pass, which will reinvigorate our concern for Glide avalanches. These avalanches are extremely difficult to predict but often occur during or shortly after periods of liquid precipitation or warming. You can’t really actively manage this type of avalanche problem, but you can avoid areas where they are more likely. You will need to look overhead and be aware of the slopes above you. If you notice signs of Glide avalanches such as crevasse-like cracks in the snow or smooth rocky slopes, give them a wide berth.

    We haven’t received much snow since the last time it rained, so that should minimize the amount of Wet Loose avalanches on Thursday. That said, keep these slides on your mind on slopes over 35 degrees if you find that there is snow available to entrain. Sinking into the snow past your ankle is a good barometer you can use to help you determine if these avalanches are possible.

    (1/12/2022)

    A glide avalanche occurred on a smooth rocky slope on the night of 1/11. The entire season's snowpack failed, exposing rock as the bedsurface. On 1/18, an additional chunk of this slope failed. 

    Photo: Alpental Pro Patrol

Avalanche Discussion

It has been a wet and warm week around Snoqualmie Pass. We had a significant wet avalanche cycle on January 11-12 when the pass received around 4 inches of rain at all elevations. That cycle included multiple Glide avalanches, many of which involved the entire season’s snowpack. Our last reported Glide activity was on Tuesday 1/18, in the Alpental Valley. The lingering activity leads us to believe that some slopes didn’t reach their tipping point during last week’s cycle and could be ready to fail given the additional rain on Thursday.

We expect the height of instability to occur overnight Wednesday and linger into Thursday morning. This is when the bulk of Wet Loose avalanches should occur if the right conditions are met. As Thursday continues, slight cooling could bring some snowflakes to the highest of elevations and strong winds might be enough to form some unstable pockets of snow to steer around. The real concern will be the liquid water and how the snowpack reacts to this additional input. Generally speaking, the snowpack should be well suited to handle the incoming rain. The January 11-12 storm and warm temperatures the past week have created drain channels in the snowpack at many elevations and resulted in a series of strong crusts. In most locations, these crusts should be able to withstand the amount of precipitation forecasted, but if you find that the surface crusts are breaking down and liquid water is making it to deeper layers of the snowpack, larger avalanches could occur.

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