Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

Sun
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Expect the avalanche danger to increase as you move out of the trees and into more exposed terrain. Gusty winds formed fresh slabs on the lee sides of ridges and along mid-slope features. Steer around steep slopes where you find smooth pillow-like drifts.

Avalanche problems

  • Wind Slabs

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

    There’s plenty of new snow out there in the West South zone from the past several days. However, in places where the wind drifted the snow into firmer and deeper slabs, you could trigger an avalanche big enough to bury you. So, as you leave the shelter of the trees or more protected basins, be on the lookout for signs of wind-affected snow. Sharp cornices, fresh drifts, textured surfaces, and smooth pillow-like slabs all indicate wind-loaded terrain. Several professionals on Friday noted that the winds were not only directly loading areas along ridges but also cross-loading mid-slope features. Some of these slabs were hard and could break above you. This makes them much more dangerous to try and manage. Once you’ve identified the winds loaded areas, then seek out lower-angled or less wind-affected terrain to avoid this problem. 

    So far, all our observations indicate the recent snow bonded well to the Christmas Crust and any inter-storm weak layers have been very short-lived. However, you could still trigger isolated storm slabs in very steep, rocky, or complex terrain.

    (12/30/2022)

    Cross-loading winds scoured slopes and built fat firm slabs. 

    Photo: Dallas Glass

Avalanche Discussion

 We’re at the tail end of a wild weather week in the West South zone. A few more inches of snow and slightly cooling temperatures should let the snowpack start to heal and the avalanche danger slowly drop. It’s easy to forget that in the last seven days we’ve swung from artic temperatures, to rain well above ridgelines, and back to winter. You may find open creeks, rushing waterfalls, and holes around rocks/cliffs. 

Since temperatures cooled and winter returned mid-week, the zone has received 15-24 inches (~1.5-2.5in S.W.E) of snow. Observations from Crystal Mt and White Pass on Friday reported the storm snow was bonding well to the Christmas Crust. However, blowing snow, scoured slopes, and newly forming wind slabs were seen. Drifted pockets failed in some (but not all) small slope tests near treeline.

More uncertainty exists around the volcanoes. Stormy weather and poor visibility limited observations on Mt Rainier, Mt Adams, and Mt St Helens the past several days. If you head to one of these locations Saturday, consider easing into the terrain by traveling on smaller and less consequential features before stepping into bigger slopes.

Regions covered