Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Snow and wind will give way to rain and freezing rain, resulting in a natural avalanche cycle Tuesday night. By Wednesday morning, the likelihood of naturals will decrease but the snowpack will be a mess and need time to heal. Be leery of large avalanche slopes or hanging blocks of snow that could fail without warning.

Avalanche problems

  • Wet Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2

    Until liquid water in the snowpack has time to drain, wet avalanches will be of concern. These slides could take various forms, such as wet loose, wet slab, or even glide. Additionally, you might see cornices sag and collapse. Regardless of what you call them or their character, wet avalanches are poorly understood and difficult to predict. You’re not going to want to hang out near large paths or under precariously hanging blocks of snow where these slides could grow large enough to bury or kill you. Consider traveling terrain as you do when high hazard is forecast, particularly on slopes with wet sloppy snow. 

    (4/7/2024)

    Rain on snow events often leave behind a mess, with intermingled wet avalanche problems. 

    Photo: Dallas Glass

Avalanche Discussion

The warm storm has arrived at Snoqualmie Pass. As of Tuesday evening, temperatures, wind, and precipitation rates are all increasing at most weather stations. Observations indicate we’re still holding onto snow, but that is expected to change in the next few hours as things get sloppy overnight into Wednesday morning.

Rain is expected to extend above the mountain peaks Tuesday night. If we were forecasting for the overnight hours, that would put us at high avalanche danger since we are predicting a widespread natural avalanche cycle. We expect the bulk of natural activity to be confined to the overnight hours, leaving us with a few rogue naturals and a messy snowpack in the morning. You’ll likely find the highest danger first thing in the morning, followed by decreasing hazard throughout the day as the storm fizzles.

The wildcard here is freezing rain. There is plenty of it forecast for Snoqualmie Pass, which could help to cap the snowpack and hold it in place. Winter lovers could consider this a good thing. It will likely help to preserve what little snow we have at lower elevations - instead of washing it away. You may not encounter many avalanches initiating in the lower elevation band, but a freezing rain crust can help slides from higher up run further than they otherwise might have. Be aware of what’s above you.

Backcountry travelers and The Summit at Snoqualmie Pro Patrol both reported 4-6” slabs on Tuesday. They were easily triggered by humans and even failed naturally as temperatures and precipitation rates increased. We’ll likely be done with dry snow problems by the time day breaks on Wednesday, but it helps to illustrate that the snowpack does not like rapid change and was adjusting accordingly.

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