Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

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

Continue to focus your observations on the interface between the new snow and the old crust. It will likely be the failure point for most avalanche activity on Sunday. Slabs will be larger and more consequential in wind-loaded terrain.

Avalanche problems

  • Wind Slabs

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

    Be suspect of slopes over 35 degrees on Sunday, particularly if they’re wind-loaded. Your full attention should be on the bond at the new/old interface. You can investigate it using test slopes or quick hand pits as you travel. More formalized assessments like compression or tilt tests can add more weight to your decision-making process. If blocks of snow are coming off cleanly, you know you have a problem. Although shallow avalanches could occur on any slope with a poor bond, wind-loaded locations should contain larger and more consequential slabs. Avoid leeward ridgelines, convex features, or drifts near cliffbands/the sides of gullies.

    (1/11/2025)

    Textured surfaces such as these near White Pass are an easy visual clue that the wind has been active and wind slabs could exist on leeward slopes.

    Photo: Dallas Glass

Avalanche Discussion

Saturday morning, a group of four backcountry tourers were involved in an avalanche accident near Kendall Peak in the Commonwealth Basin area of Snoqualmie Pass. Details are still being gathered, but the accident occurred on a SW aspect at 5600ft. All four members were caught and carried. Two were injured. The party called 911 to request assistance. Search and rescue responded to the area and brought the victims to the trailhead.

Stormy weather should subside on Sunday as we move toward a high and dry pattern. That doesn’t mean that everything is good to go. The storm snow may still need time to settle out and bond to the underlying crust. On Saturday, avalanche professionals reported stubborn but clean failures at the 1/10 interface with hand shear tests near White Pass. Similar reports from the Crystal and Mount Rainier areas paint a picture of a moderate bond throughout the zone. You may not trigger an avalanche easily, but if you find the sweet spot on an unsupported, convex, or wind-loaded feature, then watch out. In isolated locations, they could break widely or connect terrain features if buried surface hoar or near-surface facets exist at the 1/10 interface.

While storm totals haven’t been overly impressive with this pattern, the wind has. Observations from throughout the zone continue to point toward active wind transport and wind slabs on leeward features. You may find large drifts on one aspect and the adjacent slope scoured down to the crust. By Sunday, the wind should be on a downtrend but may remain gusty on the volcanoes. Eventually, we'll swap out the wind for sunshine. As the sun comes out and temps rise, take note of how the snow surface is changing. You may see rollerballs, pinwheels, or new avalanches develop such as loose. 

Before this storm, travel conditions were very challenging due to breakable crust, icy slopes, frozen tree bombs, and piles of avalanche debris. The new snow has helped, but many of these hazards are now only a few inches below the surface, making them more difficult to spot.

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