Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

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

You could still be surprised by triggering a slab avalanche in a lingering weak layer in or under the storm snow 1-2' deep. You're most likely to find this problem at shady higher elevations, and they'll be the most dangerous on large, steep slopes with trees, rocks, or cliff bands, which is where we recommend avoiding. Temperatures will get a little warmer and we're expecting to see a bit more sun than the previous day, so wet loose avalanches may occur. 

Avalanche problems

  • Storm Slabs

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

    Sunday morning a large soft slab avalanche was triggered by a rider in the Baker backcountry on the Arm.  There were several reports of slab avalanches on Saturday. The layer is slowly strengthening but you can still trigger an avalanche on this layer on upper-elevation slopes, most likely north-facing, which formed weak layers during the long period of high pressure before the new snow fell. Wind redistributed the weak layer, scrubbing it from ridgetops and possibly redistributing it downslope, resulting in lower crown lines than you might normally see.  People are still finding weaknesses and triggering avalanches within the storm snow as well, a few inches to a foot deep. Plenty of graupel was noted during this last storm, contributing to some of these potential sliding layers. 

    Slopes that are greater than 35° and especially ones that don't provide a smooth runout, aka areas with terrain traps, are locations we recommend avoiding at this time. If you trigger an avalanche you don't want to take a ride through trees or over a cliff. It may be tough to tell a slope that could slide from one that won't. Even steeper terrain, in the 40's, will be more likely to slide. You can dig down with your hand to the relatively shallow layer to check out how well the layers are bonding before committing to a slope. If you notice whumphing or long shooting cracks these are strong indicators to avoid nearby steep slopes. 

     

    (3/26/2023)

    A large soft slab avalanches (the upper one) was triggered by a rider on the Arm in the Baker backcountry on Sunday morning. The lower one is a larger, older one which was triggered by explosives last week and is now filling in.  

    Photo: Jason Speer

  • Loose Wet

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

    One observer reported "soggy" snow below treeline on Sunday. We expect to see a bit more sun and slightly higher temperatures on Monday. South-facing slopes and lower elevations will probably start the day with a crust, but this may break down and we could get resulting wet loose avalanches on the southern half of the compass on Monday. 

    Rollerballs may lead to wet loose avalanches in steep areas. 

    Photo: Trevor Kostanich

Avalanche Discussion

Wind will start picking up Monday afternoon and you may see snow redistributing. Avoid freshly drifted locations as wind slabs build, especially at higher elevations. The wind may also help to keep snow surfaces cool, slowing the moistening of snow surfaces. 

Continue to maintain springtime awareness of gaping glide cracks and looming cornices. As soon as the day gets a little warmer they'll start moving faster and gravity may win out with these unusual features, pulling them rapidly downhill.

Although we've been receiving reports of human-triggered avalanches, we've seen more people out in steep terrain not triggering avalanches as well. This was the case in the Baker backcountry, and Excelsior at Canyon Creek on Sunday. The newer storm snow fell Thursday-Friday and amounts to 1-2 ft over the old snow layer. The weak layer appears to be improving in strength and avalanches are occurring less frequently, but we're not ready to completely trust the layer yet. Even if chances of triggering an avalanche are lessening, taking a ride could still have a bad outcome. 

 

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