Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Wed
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

It's likely that you can trigger an avalanche in dry snow at upper elevations, so steer around steep slopes. Snow remains wet at lower elevations, and avalanche activity will likely have slowed, but avoid steep slopes if wet snow continues to easily slide or roll downhill. 

Avalanche problems

  • Storm Slabs

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

    Human-triggered slab avalanches are likely at higher elevations. Avalanches may be 1-2 or more feet deep. Any steep slopes are suspect, but ones that are wind-loaded will probably be more reactive. The further up you go, the larger the slab avalanches may be. 

    Evaluate how well the new snow layers are bonding by doing hand pits and using small test slopes to identify weaknesses. Pay attention to red flags, or bullseye clues such as long, shooting cracks, whumphing, and recent avalanches as obvious indicators of instabilities in the new snow, a sign to avoid steep slopes. As the snowpack continues to adjust on Tuesday, avoid slopes greater than 35°.

     

     

    (12/18/2020) Small triggered slab avalanche (D1) on a north aspect at 4300 ft. Photo: Andrew Keifer

  • Loose Wet

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

    Wet snow avalanche problems have been on the table since last Thursday 1/18. Temperatures are cooling slightly and precipitation numbers are backing off. We expect wet loose avalanche activity to slow, but not completely go away.

    During your travels, pay attention to steep slopes to see if natural activity is continuing - if you see any actively running rollerballs, or more mass picked up and wet loose slides running, stay off steep slopes and the terrain beneath them. Before heading out onto a steep slope, push a mass of snow downhill to see if it picks up more snow and/or fans out. If you are able to initiate a wet slide, keep on avoiding steep slopes. 

    Glide avalanches may occur in steep locations with smooth rock or low vegetation surfaces. Although unlikely, there's a chance wet slab avalanches may occur as well. 

    Example photo: A wide array of wet snow avalanche problems, which you might see on Tuesday.

Avalanche Discussion

If you start at lower elevations with a moist snowpack, realize that snow conditions and avalanche problems will change as you gain elevation. Remain alert to changing conditions as you travel through different elevation bands. Wet snow avalanche problems will transition to dry ones. On Monday, reports of small wet loose avalanches were still coming in, and a few slab avalanches with depths up to 18 inches and propagating wide were reported by Mt Baker Ski Area at higher elevations. 

We've had a slow and steady stream of precipitation since Saturday, totaling 2.5 inches of water at the Heather Meadows weather station. Precipitation is slowing on Tuesday and we may see a slight drop in temperature. Avalanche activity may slow a little but we're forecasted to continue with near-freezing temperatures and steady precipitation every day through the week. 

While not a major concern, we've occassionally seen evidence of very large avalanches throughout the West North zone. This shows that there are still weak layers, although gaining strength, above the 12/30 crust. It just takes a really, really big trigger to get one of these slabs moving. 

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