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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Avalanche danger varies across West Central with sustantial differences in the amount of new snow. Don’t ignore obvious signs of instability like recent avalanches or shooting cracks - these are indicators you are in an area where you are more likely to trigger an avalanche. A powerful storm will further increase danger overnight Tuesday. Anticipate changing conditions throughout the day.

Avalanche problems

  • Wind Slabs

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

    The big question for Tuesday is if wind speeds become strong enough before day’s end to make new wind slabs. Stick to lower angled, sheltered slopes if you observe active wind loading. It might be difficult to identify older slabs if new snow hides signs of previous wind loading. Though they are becoming difficult to trigger, you might still find a reactive wind slab on convex features, below ridgelines, and around cross-loaded terrain.  Upper elevation, alpine terrain is where you are most likely to trigger one of these avalanches, but treeline areas should be on your radar as well. 

    Unstable slabs might also be found in wind sheltered terrain in areas that recieved heavy snow . Use simple tests like hand shears and test slopes to assess stability as you travel. Reduce your exposure to avalanche terrain to deal with uncertainty. 

     

     

     

    Example of a small human-triggered wind slab on a convex roll. 

    Photo: Greyson Herdman

Avalanche Discussion

West Central recieved anywere from 0" to 20" of snow Sunday night and Monday with the greatest amounts likely found near Stevens Pass. Avalanche activity in areas with the most snowfall was limited to loose dry avalanches in steep but less wind affected terrain. There were no observations from higher elevations. Reported avalanche activity in West North  - which recieved 6" of new snow Sunday night - was limited to roller balls and very small loose wet avalanches on solar aspects.

The most recent snow now makes for 1' to 2' of cold and dry snow over a strong snowpack of rounded grains, melt forms and crusts. Weak, faceted snow and surface hoar that developed during November’s drought didn’t likely survive in most areas due to temperature inversions, strong sun and alpine winds. Rain preceding snowfall on November 22nd probably soaked whatever surface hoar and facets remined. Upper elevation terrain and areas farther east in the zone (that experienced colder temperatures and less/no rain) may still have pockets of weak snow existing under new snow layers. There is no information from less traveled terrain near the Cascade crest or alpine terrain in general. Be prepared to look for and assess this layer if you travel in these areas.  

Despite the latest storm - and more snow on the way this week - it's still early season and the snowpack is still shallow. Many hazards remain including exposed or barely buried trees and rocks, open creeks and other rugged terrain features.  

If you are out and about in the mountains, let us know what you find by submitting an observation.

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