Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

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

Another modest storm could build a fresh batch of potential avalanches in wind-loaded terrain by Friday morning. Look for lower angled or less wind-affected slopes to steer around these slightly thicker and firmer slabs of snow.

Avalanche problems

  • Wind Slabs

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

    The snow totals on Friday morning aren’t likely to catch your attention but the overnight winds should easily form a new round of wind slabs for you to navigate. One unique twist to this latest iteration; an inch or two of soft snow could hide some of your normal visual clues. Look for drifts behind trees/rocks and sharp cornices to discern local wind loading patterns. You’re most likely to bump into this problem on the lee sides of exposed ridgelines, along the base of cliffs, and in the top of chutes. Since you may not be able to clearly see the edges of the wind slab, give them a bit more space. 

    In many areas, these slabs should remain relatively small and only pose a risk if they knock you off a cliff or flush you down a couloir. However, in locations that receive more snow, some of these slides could grow large enough to bury you.

    (2/9/2023)

    This uptrack test on a wind loaded slope produced obvious cracks. 

    Photo: Susie Glass

  • Loose Wet

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

    This problem is far from a slam dunk, but we’ve reached that time of year where sunshine post storm typically results in natural loose wet avalanches. We think skies will break enough on Friday to allow the sun and warm temperatures to cause the snow surface to become wet and unstable. Look for new rollerballs and snow shedding from trees to anticipate this hazard. If you see these signs, pay attention to the terrain above you, and don’t let one of these slides push you into a creek or over a cliff. 

    We think loose wet avalanches will be the most dangerous at mid-elevations where enough new snow exists to produce legitimate slides. At lower elevations, less snow should limit the size and hazard of this problem.

Avalanche Discussion

This seems to be the winter of modest storms and wind slabs in the West South zone, and Friday falls right into that theme. Per normal we expect the hazard and avalanche size to be the greatest near the volcanoes where more snow should accumulate. However, since this is primarily a wind-driven issue, you’ll still deal with the same problems closer to the crest. 

On Thursday observations from all across the forecast zone indicated small lingering pockets of wind-loaded snow. However, the main story of the day was the numerous rollerballs and small loose wet slides. This warming also resulted in a new surface crust at lower elevations and on southerly aspects. At mid and upper elevations shaded terrain, cold dry settled snow was reported. 

This could result in a variety of surfaces for the snowfall on Thursday night. As a result, you may notice the upper snowpack responds differently from one slope to the next. Use lots of small slopes and hand pits to test the new snow and see how it fails.

Regions covered