Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

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

Identify and avoid steep terrain features where you find recently wind drifted snow.  Loose surface snow in more protected terrain will still run down the slope with human triggers or if provoked by snow shedding from cliffs warming in the sun.

Avalanche problems

  • Wind Slabs

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

    Be on the lookout for fresh wind slab in addition to older slabs from the last storm. Northerly alpine winds should not be strong, but they will have access to plenty of soft snow to drift onto more southerly slopes. Expect to see more wind transport in the northern and eastern portions of the forecast zone.

    You are more likely to trigger a wind slab on steep, convex features just below ridgeline. Also, be wary of gully walls and unsupported areas above or around cliff bands. Blowing and drifting snow will show you which slopes are accumulating fresh wind slab. 

    Slabs from the last storm are probably trending towards stubborn or unreactive, but it’s still worth evaluating the uppermost layers with hand pits, test slopes, and other informal tests. To find older slabs you will need to monitor changes in new snow depth and stiffness as you climb higher and change aspects. The depth of snow over the buried crust should serve as a convenient reference point.  While the likelihood of triggering one of these is lowering, they will still be out there on Sunday.

    (2/21/2023)

    Wind rippled surfaces and cornices are signs the wind was at work. Steep unsupported features are where you are more likely to trigger one of the slabs they built.

  • Loose Wet

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

    Expect to see a fair bit of sun that should cause steep cliffy or treed terrain to shed snow and start loose snow avalanches on slopes below. These avalanches aren't exactly 'wet' but have plenty to do with warming. Keep an eye on what is above you, especially during periods of warming or sun. Limit travel on or directly under sunny slopes where you see rollerballs or fresh loose snow avalanches.

    (1/27/2023)

    An example of rollers and small loose wet on a slope seeing direct sun. These are early signs you might see larger avalanches.

    Photo: Julz Holder - Grounding Truth

Avalanche Discussion

Loose dry avalanches big enough to knock you over and carry you down the slope were reported Saturday and should still be in play.  Keep track of how much snow is moving with you if you venture onto steep slopes and be ready to pull off the side to let it run by.

Observers in the Baker Backcountry reported plenty of wind drifted snow. Slabs up to 3’ deep over the crust buried on Jan 10th were easy to find, but most of the reported avalanches were only 6-12” deep. One test slope produced a deeper slab which failed just above the crust buried on January 10th. 

On Friday, observers reported shallow slabs that were easily triggered on wind loaded slopes at mid and upper elevations. Signs of instability and avalanche danger generally increased when climbing into upper elevations where the wind had created more of a slab. Warming also made the snow more slabby and moist snow was found at the surface at and below 5000’.

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.

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