Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

One more day of easterly winds and cold temperatures before a pattern change at Snoqualmie Pass. Hard wind slabs are more difficult to assess and test, but you can still avoid them by identifying wind-loaded features. Deeply buried weak layers should be on your mind as you travel and as our next storm approaches.

Avalanche problems

  • Wind Slabs

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

    It won't be hard to find evidence of the recent windy weather. Slabs formed over the last few days will react differently based on their age and firmness. The most sensitive slabs should be at mid to upper elevations on convex features, near ridgelines, or in confined chutes/gullies. You'll likely encounter plenty of hard slabs out there, which are more challenging to manage than our typical soft slabs. They may feel hollow and are notorious for surprising travelers and professionals alike. Look for areas that appear "fat" compared to the surrounding terrain and are more dense. Nearby, you may notice textured surfaces or fresh cornices. Since the wind has been coming from an atypical direction, slabs may have formed on aspects or lower down in the terrain than where you're used to finding them. You should avoid any feature you suspect is wind-loaded.

    (1/14/2024)

    How many crowns can you find in this image? Note how most of them are on convex features or the base of rocks. Exactly where wind slabs like to form.

    [N Slope of Chair Peak]

    Photo: Steven

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2–3

    Our poor snowpack structure comprised of the 12/30 and Solstice Crusts persists within the zone. We have been tracking these layers for weeks and have seen them come alive in neighboring zones in recent days. We only have one suspected avalanche on them at Snoqualmie Pass. However, observations during the sunny weather lead us to believe there may have been more. The real question moving forward is, what would it take to trigger an avalanche on these layers?  Our best guess is it will take a larger trigger, such as a cornice collapse or another avalanche. Our theories may be tested on Wednesday and Thursday as snow returns to the Pass on a slight warming trend. Until that time, talk with your partners about your acceptable level of risk and avoid big open terrain if you want to minimize your exposure to this hard-to-forecast avalanche problem.

    (1/10/2024)

    This very large avalanche released remotely from nearby explosive placement during avalanche control at Alpental. It is an indication that deeply buried weak layers could still be active. 

    Photo: Alpental Ski Patrol

Avalanche Discussion

It was another cold and windy day at Snoqualmie Pass on Monday, with no new avalanches reported. Travel conditions continued to be a mixed bag of wind-effect in exposed areas and well-settled powder in more protected locations. The greatest indication of instability is recent avalanches, and we have had a lot of those recently. The majority of public observations from the weekend contain a picture or mention of a recent avalanche crown. There have also been plenty of reports of the surface weakening ahead of this next storm in areas protected from the wind.

Tuesday will be a transition day as clouds move into the area, and there is even a chance of a flurry by sunset. Expect a significant uptick in avalanche potential on Wednesday as the next storm takes aim at the zone. We will anxiously await how those deep persistent layers react to additional loading. The 1/8 and wind slabs may bridge them, or it could go off, and we'll see large, unsurvivable avalanches aplenty. That's the uncertainty we're living with right now as a community. Time will tell, but it may not be a good night for a camping trip. 

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