Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
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Out of date — this forecast expired 2 years ago.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

Another hot and steamy day at the Pass will maintain the conditions needed for wet avalanches on Sunday. If you're not traveling on a firm crust, then you need to be thinking about wet slides. Be mindful of slopes above you, and don't push snow down on people below you.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Loose wet avalanches often occur as snow sheds from trees or rocks before gathering surface snow and fanning out. You likely won’t find much snow in the trees right now, and the amount of snow clinging to rocks on sun-exposed slopes is dwindling. But the surface is wet and weak, ready for a push to start it moving downhill. That something could be you. Recent observations indicate the snow has been “ripe” for pushing in the morning hours. Use careful travel techniques, being aware of what (and who) is above and below you. Limit your exposure to terrain traps where even small avalanches could become more consequential.

    (4/13/2024)

    Layers of wet avalanche debris coming out of a confined chute. You can see where one slide gouged down into deeper snow layers. This is a relatively shaded and cold slope. It likely is a mix of natural and human-triggered slides.

    Photo: Andy Harrington

  • Glide Cracks

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2

    Whether our winter snowpack falls down in chunks or slowly melts away, only mother nature knows. But larger shed-style avalanches often occur after a few nights without a hard freeze. Saturday night should be the warmest of the week, so on Sunday, you could see more of these unpredictable slides. Be aware of slopes baking in the sunshine, even far above you. Limit your time spent under cornices, hanging blocks of snow, or on slopes with large crevase like cracks.

    (4/13/2024)

    Debris from a large glide avalanche which brought down rocks and small trees in addition to snow. 

    Photo: Caya Johnson

Avalanche Discussion

All that snow has to come down at some point this spring. Prolonged periods of hot weather are a prime time to start that process. We’ve been through a few of these already in the last month. You may know the drill by now if you've been paying attention. Surface snow will start to shed first, like layers peeled from an onion. We often categorize these as loose avalanches, and they were reported throughout the zone on Saturday as temperatures soared into the 50s. Evidence of their existence is not difficult to find.

Expect a warm night on Saturday, followed by another scorcher on Sunday. Enter phase 2 of the spring shed cycle. As meltwater percolates into the snowpack, larger, more unpredictable slides often follow. These can take many forms, such as glide, cornice, wet slab, or just plain old blobs of snow falling off things. They can trigger slabs or create loose slides on moist slopes below, traveling far distances and growing large. On Saturday, NWAC forecasters witnessed a few small shed-style avalanches in the Alpental Valley.

Overall, the snowpack is still transitioning from winter to spring. While it may no longer be found on the surface, dry snow and layers still exist below the warm, moist snow. Until the snowpack becomes isothermal and the surface freezes, you’ll need to manage wet avalanche problems and potentially some surprising avalanches. Exposure and likelihood may be less in the morning hours before the heat of the day, but that’s not a guarantee. These slides can happen at any hour.

Slopes that have repeatedly seen direct sunshine over the past month have thinned significantly compared to those on the shaded side of the dial. As you journey through the mountains, you'll need to contend with open creeks, holes, thin coverage, and avalanche debris. Bring the right tools and have a plan for managing these hazards.

This is the last avalanche forecast for the 23/24 season. NWAC will continue issuing mountain weather forecasts each afternoon at 2:30 pm through April 28. We’d like to thank each of you for reading and using these forecasts to make informed, safe decisions and for contributing to your community by submitting observations. Please continue to help support your backcountry friends by letting others know what you find in the mountains. Have a wonderful spring and summer. - Andy and Dallas

Additional Commentary:

To say that this season has been challenging could be considered an understatement. Dealing with El Nino and pesky, persistent weak layers was a break from the norm but part of the typical job stressors. Losing colleagues and friends in the mountains was a gut punch many of us at NWAC were unprepared to deal with. I can personally say that this was the most demanding forecast season I have had to endure. Thanks to everyone who supported us emotionally. 

Additional thanks to those who continually fed us observations or who donated time/money to our non-profit branch. It all helps NWAC provide information so that you can hopefully travel safely in the mountains and go home to your loved ones at the end of the day.

Your friends miss you, Matt. R.I.P.

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