Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Backcountry travelers should still be wary about moving across or below steep slopes of wet snow. You are most likely to encounter an avalanche on southerly slopes that become even more unstable under a strong sun. High freezing levels will sustain wet avalanche danger into the weekend.

Avalanche problems

  • Wet Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3

    Though the rain has ended, high freezing levels and potentially strong sun on Friday will delay the snowpack refreeze we hope for after rain events. Danger from loose wet avalanches, wet slabs, glide avalanches, and falling cornices are still factors to consider in avalanche terrain until we get a significant decrease in temperature. Wet slab and glide avalanches can happen long after heavy precipitation ends as water continues to percolate through and weaken the snowpack.

    Avoid traveling under sagging cornices, glide cracks that indicate the entire snowpack is slipping on the ground below, large, unsupported blocks of snow on rock faces, or slab avalanche hangfire. These are not dangers that can be precisely anticipated or “managed" - all you can do to reduce risk is stay away from steep terrain features that could still produce large, wet avalanches. Though the likelihood is low any of these hazards will release naturally in terrain above you, the consequences would be devastating.

    Smaller but still dangerous loose wet avalanches could be triggered in steep terrain where you are skinking past your ankles in wet snow.

    (1/11/2022) Glide cracks and small glide avalanche north facing Mt. Herman above Bagley Creek.

    Photo: Lee Lazzara

  • Deep Persistent Slabs

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

    In the West North we are still suspicious of a layer of surface hoar buried on December 21st. It produced a handful of very large avalanches centered around Shuksan Arm in late December. Some released naturally while others were triggered with avalanche mitigation work. The added weight of rain on the snowpack the last three days plus high freezing levels will make for a good test to determine whether any more large, alpine slopes could release on this layer. 

Avalanche Discussion

Heather Meadows received over 6.5” of precipitation from January 10th to midday on the 13th. It fell nearly all as rain except at the highest elevations.  The rain fell on a cold, dry snowpack near and above treeline and triggered a natural avalanche cycle consisting of numerous loose wet, wet slab and glide avalanches. Below treeline areas saw significant rain earlier in January and less avalanche activity was reported from this elevation band in the West North.  

Three days of rain plus high freezing levels into the weekend have us on guard about the state of the snowpack. Lots of rain water free-ranging through cold snow layers and freezing levels of up to 9000' in January make for an unusual setup. Unusual weather makes for an unusual snowpack with makes for unusual avalanches. With this in mind take nothing for granted the next few days when it comes to evaluating risk in avalanche terrain. 

If you make it to the alpine in good weather on Friday, you may encounter unstable storm and wind slabs in the highest terrain. Assume more dangerous avalanche conditions if you find dry new snow that is rapidly warming with sun exposure and/or very high freezing levels.

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