Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Freezing levels are rising to 8000 feet Sunday afternoon in the West Central Zone. Avalanche concerns are shifting to wet snow problems, so if the snowpack is wet and you notice rollerballs running down a slope, stay away from those areas. On shady slopes especially at upper elevations, wind may have redistributed light snow into thicker, reactive deposits, something to avoid on Sunday as well.

Avalanche problems

  • Loose Wet

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

    Freezing levels are forecasted to rise to 8000 feet Sunday afternoon. Skies may actually clear for a day before clouds return. This, in combination with low-density surface snow from the last few days, primes us for wet loose avalanches. Clear skies will probably limit the problem to sunny slopes, but if clouds develop, wet loose avalanches could run on all aspects. 

    Pay attention to snow surfaces as you travel. If the snow begins to get wet and clumpy, and if you notice rollerballs or small wet loose avalanches running down a slope, steer clear of similar slopes and the runouts beneath them. They will probably remain limited to the low-density surface snow. Depending on how warm it gets, they could fan out and become large enough to catch and carry you or cause more damage if you’re near a terrain trap. If they’re running on sunny slopes, consider shifting to shady, more northerly aspects where you may not find that problem.

    (12/21/2021)

    Rollerballs like these are good indicators that the snow surface is getting wet and wet loose avalanches may follow (on a larger slope)

    Photo: Matt Primomo

  • Wind Slabs

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

    Low density snow in some upper elevation areas transported into thicker wind slabs in recent days and overnight. It is possible that you could trigger an avalanche on these slabs. These avalanches could be a few inches or a foot or two deep. Search for textured snow surfaces, pillows, or firmer feeling snow. Keep an eye out for shooting cracks. Start on smaller terrain before stepping out onto larger slopes. If the slabs are hard, they tend to break above you, meaning it is very difficult to escape them. These harder slabs may be disguised with lighter snow on top. If you find any signs of wind-loaded snow, shift to areas that are non- wind-affected or stay on slopes less than 35 degrees.

    (4/11/2021) Wind slabs at upper elevations in the top foot of the snowpack could occur. This is an example of a small snowmobile-triggered one on a convex slope. Photo: Andrew Kiefer

Avalanche Discussion

A lot of variability exists in snow conditions throughout the West Central Zone on Sunday. Some areas could maintain a cool breeze keeping wet loose avalanches at bay, while other areas may have more wind transported upper elevation snow to tread carefully around. Glide avalanches may also be coming to life as temperatures increase and water percolates through the snowpack. This is especially the case on sunny slopes with smooth underlying rock or grassy surfaces.

We just completed a large storm cycle that lasted from January 2 to January 7 with a small lull on the 5th. Several inches of water fell, some as snow (3 - 4 feet at mid and upper elevations), and some as rain, especially below 4000ft. Temperatures generally trended warmer as the storm played out, and lower elevation snow was beaten back with rain. Road travel has been challenging, weather stations struggled, and observations are limited due to accessibility challenges. There are a lot of things we don’t know about these new snow layers. The snowpack is slowly stabilizing but continue to exercise caution with all these uncertainties in the conditions.

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