Avalanche forecast

West Slopes North

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Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

We’ve picked up several feet of new snow over the last three days. You will be able to trigger avalanches on steep, wind drifted alpine slopes. Stick to less steep terrain, or places where the snow isn’t wind affected. Although lower elevations are less dangerous, continue to use caution in steeper, obviously wind-drifted areas.  

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2.5

    Several feet of new snow and moderate to strong winds have created a patchwork of drifting patterns and shallow instabilities. For reference, the Heather Meadows weather station recorded ~3.8 inches water / ~44 inches of snow in the last three days. 

    There was a natural avalanche cycle late Sunday night or early Monday morning, and on Tuesday we received several reports of smaller natural and human triggered avalanches in wind affected snow.  These more recent wind slabs were soft, 6-10 inches deep, and in the D1-D2 range. Some were ‘stubborn', or hard to trigger, and some were fairly ‘touchy’, or easy to trigger. Almost all of the reports are from lower and mid elevations (probably because conditions are keeping people out of the upper elevations) and it's likely that upper elevation slabs are larger, more unpredictable, and more dangerous. 

    So far we have no reports of larger avalanches in the storm snow, but take that for what it is worth – visibility was mostly poor over the last two days. 

    There is some uncertainty (especially in the alpine) around the distribution, sensitivity, and size of these wind slabs. It's a good idea to avoid steep, wind loaded terrain – especially if the runout is consequential. 

    (1/4/2022)

    Small avalanche in wind affected snow. Observers report easy triggering of 8-15 inch soft slabs in steep areas near and below treeline (on Tuesday).  

    Photo: Zack Mcgill

  • Deep Persistent Slabs

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

    Two explosive triggered avalanches and two natural avalanches were triggered deep in the snowpack on the Shuksan Arm over the last week or so. Check out one of these avalanches HERE. All of these avalanches occurred on steep, unsupported alpine terrain features.  

    The layer in question seems to be a layer of surface hoar which was buried prior to Christmas. We’ve had several storms since then and at this point the layer is probably between 4 and 7 feet deep. Although we don’t have any reports of big avalanches occurring on this layer as a result of the recent storm load, visibility has been poor and information sparse.

    The take-home is that an even small possibility of very large avalanches triggered deep in the snowpack is another reason to steer clear of large, wind-loaded slopes and their run-out zones. 

    (1/1/2022)

    Surface hoar line visible in crown profile where D3 (very large) avalanche failed on the Shuksan Arm. This layer is probably 4 to 7 feet deep on 1/5/22.

    Photo: Simon Trautman

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