Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

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

While the snow totals may not catch your attention, the wind has been hard at work drifting the snow into thicker and firmer slabs. You may trigger an avalanche on steep slopes where you find pillow-like slabs or in areas below sharp cornices. Steer around these wind-loaded features.

Avalanche problems

  • Wind Slabs

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

    Small wind slabs were already forming on Sunday near Crystal and White Pass. Additional snow and continued winds will only increase the size, depth, and distribution of this problem. While these slabs won’t be everywhere, you’ll need to have a keen eye to discern which features hold wind-loaded snow hiding under a few inches of soft powder. Look for classic clues like sharp cornices, large drifts, and slopes that look “fat” to help you anticipate steep areas you want to avoid. You’re most likely to find them near exposed ridges, in rock-walled chutes, along the base of cliffs, and on cross-loaded features. Since most of these slabs should be avoidable, just go around them by using lower-angled or less wind-affected slopes.

    (1/15/2023)

    A small human triggered wind slab from the Crystal backcountry Sunday. 

    Photo: Public Observation

Avalanche Discussion

Additional snow Sunday night will once again favor the volcanoes. Places like Paradise and Mt St Helens could receive another 6-8in of snow before the morning. In these locations, you could see locally higher danger if more snow falls than forecasted. By Monday, precipitation should start to taper, and winds ease. As a result, you’re likely to encounter the greatest avalanche hazard in the morning. As the day progresses, you may see wind slabs gaining strength and becoming harder to trigger. 

The snowpack has already started to change quickly from the wet and warm weather of last week. Most sites picked up 4-6in (10-15cm) of snow Saturday night into Sunday. This all sits over the new 1/14 crust. You may find that any avalanches failing on this crust run quickly. Outside of wind-affected areas, we expect the new snow to be right-side-up but potentially poorly bonded to the firm older surface. This could result in small loose dry avalanches in steep terrain. Don’t let one of these sluffs knock you off your feet in high-consequence areas like above a cliff or creek. 

While the new crust is gaining strength, it is still relatively thin (2-4in/ 5-10cm) and breakable. This could pose its own challenge as you travel. Water from last week's atmospheric river has reached into the snowpack. Runnels along the old surface indicate water is draining. While we could still find the 1/4 surface hoar layer at Crystal Saturday, this layer appeared to have been wetted in those locations. The biggest thing you’ll likely notice from last week’s rain event is the piles of frozen wet avalanche debris that litter the mountains. Several observations from the past few days have painted a picture of a relatively widespread natural wet slab avalanche cycle up to size D2.5. Now that temperatures have cooled and the surface is frozen, the wet hazard should finally be put to bed.

Regions covered