Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Keep an eye out for unstable slabs of wind-drifted snow at mid and upper elevations. The likelihood of triggering an avalanche may increase in the afternoon if the wind begins to transport snow into fresh slabs. Unusual avalanche activity warrants additional caution in steep terrain.

Avalanche problems

  • Wind Slabs

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

    There is still a risk of triggering a wind slab avalanche even though the overall danger continues to decrease with time. If you do find one, it will likely be small and in steep, unsupported terrain near ridgelines. On the other hand, one recent avalanche (details in discussion) shows it’s still possible to trigger a larger more dangerous wind slab, potentially from the middle of the slope or below it. The likelihood of triggering one is low - but the consequences could be high if you do.   

    Be on the lookout for rounded, pillowy-looking drifts perched over steep terrain, above or around cliffs, and under cornices. Snowpits and testing might give you more information to gauge stability. The easiest way to reduce risk is to use a lower-angled line to navigate around suspect slopes. 

     

    (12/6/2022)

    A large, rider triggered wind slab. It released when the person was lower on the slope. They were caught and carried to the bottom. 

    Photo: Matt Lubar

Avalanche Discussion

Observers today noted little change in conditions from the last few days. Less visibility, minor wind transport, and a bit of new snow were the main themes. The pattern should remain the same tomorrow morning. Expect increasing winds in the afternoon ahead of a storm on Wednesday night into Thursday.

Since the last loading event Dec 2nd most human triggered avalanches have been small and shallow. It’s worth noting that few were reported despite a very busy backcountry weekend. They tended to involve the uppermost, most recently deposited layers. Slabs like these tend to gain strength quickly and often become difficult to trigger within a few days.

One unusual avalanche outside of the typical pattern occurred Sunday. It was larger, notably deeper (4’ at the crown), and released above the rider who triggered it. The weak layer was observed as small faceted grains above a hard crust. While definitely an outlier, it’s still a large, deep avalanche in the middle of a very popular area triggered by a human. Keep this in mind and take the extra time to investigate and get a feel for the snowpack where you travel.

Speaking of snowpack . . . strong sun over the weekend left a stout suncrust on solar aspects. Shadier slopes - in some areas topped with surface hoar or weak faceted grains - still hold soft snow where not wind-affected. Near treeline there's generally 2-4 feet of settling snow over a rain crust buried on Nov 25th. Below are alternating layers of rounding facets and hard crusts to the ground. 

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