Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

It's finally cooling but the precipitation isn't shutting off yet -although now we'll at least be getting snow. Near and above treeline, the new snow, which could amount to a foot by the end of the day, could form into thicker drifts along ridgelines and around features, which are areas to avoid on steep slopes. If you see glide cracks, there's still a small chance that they could avalanche, so do not linger beneath these gaping cracks. 

Avalanche problems

  • Wind Slabs

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

    Size and reactivity of wind slab avalanches could differ depending on where you are in the zone and how much snow we get. We expect about a foot of snow near and above treeline by the end of the day. Danger is expected to increase as the day progresses. Moderate to strong winds will redistribute snow into drifts which could avalanche with a human trigger. Search out fresh drifts which you can expect to see in the usual locations on or below ridgelines, on convex rolls, and around features. Avoid these locations on steep slopes. Search for obvious clues like long shooting cracks as indicators to avoid nearby slopes greater than 35. 

    The new snow may bond well to the underlying heavier and more moist snow. You're most likely to trigger an avalanche within the new snow layer, probably less than a foot deep. However, if you do make it above about 6000ft, a lot of snow fell during this storm and there is a very small chance a deeper avalanche could release, although this is unlikely. 

    (1/9/2023)

    Wind slabs like this could fail on steep slopes with a human-trigger.

    Photo: Irene Henninger

Avalanche Discussion

Neighboring zones reported varying amounts of avalanche activity on Monday. The West North zone had cooled a little and most wet snow concerns had dissipated.  Stevens Pass and Snoqualmie zones were seeing wet loose avalanche activity and glide avalanches. We expect there to be less activity by Tuesday as temperatures continue cooling. Keep glide avalanche concerns on your radar, however, and travel hastily or avoid slopes beneath glide cracks during your outing on Tuesday. 

As of Monday night, around 4" of water has fallen since Thursday in the West Central zone. Snowlines mainly hovered in the 4000-5500ft range. Above 6000ft or so, there is likely several feet of snow from this system. Winds gusting extreme on Sunday likely redistributed a lot of this snow into very thick slabs. The "warm" temperatures up high likely kept slabs stubborn and not as reactive as they might be if snow was cooler, low-density powder. Despite cooling temperatures, an insulating layer of new snow and residual heat and moisture in the snowpack is expected to keep the snowpack moist and softer for a few days. A crust may form on the surface of the old snow layer, something to keep in mind for your outing on Tuesday. 

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