Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Fresh slabs of wind drifted snow are the primary danger at mid and upper elevations. Utilize a lower angled line to reduce the likelihood of triggering an avalanche in wind loaded terrain. Use extra caution in rolling terrain or during poor visibility to mitigate the danger from early season-like hazards. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Deep, thick wind slabs were found  pretty much everywhere but were unreactive on a short, steep slopes at treeline. You might still trigger one in unsupported terrain on Tuesday. Since signs of wind transported snow are also pretty much everywhere, track the snow depth over the rain crust below to hunt down areas holding deeper slabs.  Strong winds may have created a more haphazard loading pattern than normal

    Slope tests didn't show much on Monday as the slabs were just too thick and "sticky." Hand pits did show where you could get a more planar shear and therefore where the likelihood of triggering a slab was higher. The best bet will be to just steer around steep, convex, wind loaded features where the slabs have the least amount of support from below. 

     

    (1/16/2023)

    A basic profile of wind loaded slope.  The rain crust was 20-30cm deep in most locations but deeper in some (like this site) while exposed at the surface at others.

Avalanche Discussion

Non-avalanche hazards include dense, grabby new snow, patches of exposed crust, frozen avalanche debris, exposed creeks, and other natural hazards exposed by recent rain. Multiple observers out on Monday noted they felt the greatest hazard was not avalanche-related, but dealing with any or all of the above in poor visibility.

Many of us found the latest storm underwhelming. About 10” of new snow from .87” of snow water equivalent (SWE) was recorded at Heather Meadows - about 50-75% of what was expected. Other weather stations around the zone picked up 0.2-0.7” of SWE. 

Wind gusts to the low 40’s redistributed snow down to 4000’. Near treeline, dense wind slabs and stiff snow were found nearly everywhere between patches of exposed rain crust and buried avalanche debris. But the slabs were generally unreactive and testing produced little in the way of results.  No new avalanches were reported other than a few wind slabs triggered by avalanche control work. 

Keep an eye out for and reduce exposure to glide cracks and hanging slabs in steep rocky terrain above. The sun is not forecast to make an appearance, but if it does look for the usual signs of instability like wet, unsupportable snow surfaces, rollerballs, or small avalanches. Stay off and away from steep slopes if you to observe any of the above in your travels

If you’re out in the mountains tomorrow, consider submitting an observation.

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