Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 3 years ago.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

Highlights

Fresh snow and strong wind equals unstable new slabs. Use lower-angle terrain to bypass steep slopes that are collecting wind-drifted snow. You could see widespread instability and even a few natural slab avalanches by the afternoon. Monitor changing conditions and defer to sheltered terrain to find less avalanche danger.

Avalanche problems

  • Wind Slabs

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

    Expect an increase in wind speeds to build fresh wind slabs. Weather stations show West North probably picked up a uniform 4-8" across the zone with more snow at higher elevations. With plenty of snow available for transport, expect legitimate wind slabs by afternoon, potentially earlier.  This could be one of the days when avalanche hazard sneaks up on backcountry travelers who start out expecting to not trigger anything. 

    Blowing and drifting snow will point the way toward the slopes where you are most likely to trigger a fresh wind slab. Changes in snow stiffness and scoured surfaces will also help identify slopes holding fresh slabs The best policy will be to simply steer around steep slopes where you observe active wind loading.

    (1/4/2023)

    Active wind transport should show you exactly which slopes are loading up. 

Avalanche Discussion

It was a quiet day with sunshine, cold temps, light winds, and some new snow.  Scattered clouds drifted in and out over the course of the day and were reported to hold warming in check.  In areas that saw more sun, you might find a thin crust on solar aspects. No natural avalanches from the latest storm or human-triggered wind slab avalanches were reported.

At mid-elevations the 4-6" of new snow wasn't quite enough to keep you off the frozen crust below. Deeper snow was found above 5500' with drifts up to 2' deep just below ridgeline on north and east aspects. Most observers found the new slabs were unreactive despite the presence of a layer of softer snow between denser layers. The new snow was also well bonded to the old and wet - but now frozen - snow surface in wind-loaded areas. 

The snowpack below the crust consists of wet or moist melt form layers alternating with harder crusts. The existing snowpack (below the new snow) is more reminiscent of a strong, fully transitioned summer snowpack versus what we would see in a typical December.

The new snow barely conceals a number of creek holes, rocks, and even patches of bare ground that melted out in previous days. Old avalanche debris should also be on the checklist of non-avalanche hazards.

Regions covered