Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Fri
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Out of date — this forecast expired 3 years ago.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

Get ready for a big change in conditions. Avoid steep slopes with fresh, wind drifted snow as conditions deteriorate and the storm gains strength. Anticipate greater danger than forecast if there is more than 6” of new snow along with strong winds and active loading.

Avalanche problems

  • Wind Slabs

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

    The crux of the forecast is the timing between strong winds and new snow. There just isn’t much snow available for transport other than a few inches forecast to fall overnight. If snowfall picks up when the winds are still cranking Thursday, it won't take long for reactive slabs to build over slick crusts, weak facets, or both. Either way, the avalanche danger will be greatest at the end of the day.

    Areas of wind slab will be easy to identify. Look for drifting snow and smooth surfaces surrounded by old tracks, rollerballs, avalanche debris, etc. While the new slabs shouldn’t get very big, they might be more reactive than usual given the crusts and facets below them. 

    Wind slab formation could look like this Thursday. Smooth sections of wind drifted snow surrounded by old tracks. The only place with good snow is the only place you could trigger an avalanche.

Avalanche Discussion

Glide and wet avalanches should still be on your radar despite colder temperatures. Glide avalanches have occurred days after it cools off. You could see rollerballs and small wet loose if sun breaks warm up freshly fallen snow. Also be on the lookout for glide cracks, avalanche debris, and any other hazards left over from melting, spring-like conditions. Dry new snow with the coming storms will start covering these but they will still lurk just under the surface.

A wide variety of wet avalanche types was observed around the Baker BC Wednesday. Most of the larger ones look to have run the day prior, triggered by strong sun combined with already warm temperatures. The rock slab above the Boulderfield on Herman shed its snowpack and it ran a bit less than halfway to the lake. A large slab avalanche was observed high on the south face of Sefrit, likely triggered by a smaller avalanche from above. 

More large wet loose and glide avalanches were scattered in the surrounding mountains. They were not everywhere, but there were enough to indicate a significant natural avalanche cycle. No observations were submitted from other areas of West North.

A surface crust can be found on all aspects to at least 5500’. An inch or two of new snow from a few days ago is faceted and found above the crust on shaded aspects. South facing slopes warmed nicely today and made for beta-corn conditions on a still-supportable crust at noon.

 

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