Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
2 · Moderate
Treeline
1 · Low
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Out of date — this forecast expired 3 years ago.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

You could still trigger an avalanche on steep, wind-drifted features on Tuesday. Search for thicker deposits, textured, or wind-featured snow, and steer around these locations on steep slopes, which you're most likely find near and above treeline. The place you're most likely to trigger an avalanche is very steep, committing terrain, so even though an avalanche will probably be small it could still take you for a scary ride. 

Avalanche problems

  • Wind Slabs

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

    Yet another dose of light snowfall and moderate winds could be enough to replenish or create new slabs in above treeline terrain. You may also see new slabs and greater danger affecting near and above treeline if more snow or stronger winds than forecast occurs. Evaluate for wind slabs by identifying actively drifting snow or textured surfaces. Slabs could lurk beneath cornices, or you might find them by experiencing long, shooting cracks or changes in snow depth and stiffness. If you notice any of these clues, steer around steep nearby slopes. Be sure to identify whether a slope you're considering traveling onto has any accompanying terrain traps which could make even a small avalanche deadly. You're much less likely to encounter an avalanche in terrain with no wind effect or loading. 

    An old photo of small wind slabs running from steep, featured terrain in the West North zone.  Photo: Robert Hahn

Avalanche Discussion

I traveled to the south side of the Mountain Loop Highway on Monday. You can check out my observation HERE for more details.  In short, I found crusty snow surfaces on the south half of the compass. Low-density powder was still in abundance on the northerly half. This means snow surfaces aren't as pleasant for travel on sunny aspects, but avalanches are less likely, and there also isn't much snow that's capable of being transported by wind off these aspects. Meanwhile, north-facing terrain is holding onto cold, dry snow, and plenty of low-density snow exists. Wind can transport this snow if it wraps around to these aspects, and it's where you're more likely to encounter avalanches. This is probably one of the easiest assessments you can do during your outing, as you'll likely gravitate away from crusty areas and search out powder where there's also more potential for wind slabs up high. I dug pits and found a right-side-up snowpack in my north-facing pits, with no results yielded from tests. This was near treeline, but other locations and especially higher in elevation may harbor wind slabs that could react to a human trigger. Take a minute to investigate steep slopes for these slabs before jumping out onto them. 

Conditions have remained similar in the area for a few days now. We're seeing a mix of sun and clouds with temperatures that aren't quite getting too warm. Scattered showers are continuing, with not enough snow expected to amount to an increase in avalanche danger. Wind will be a little stronger, so keep an eye out for new small slab development at upper elevations. Regarding wind, pay very close attention to cornices and your proximity to them. They've grown very large and could break with or without an obvious cause. Just a breaking large cornice is scary enough, but if there's anything that could trigger an avalanche it will be one of those. Stay very far back from the edge, and avoid or travel very quickly through terrain beneath these saggy features.  

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