Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Tue
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Heavy snowfall will likely cause a natural avalanche cycle at upper elevations over the next 24 hours. Peak hazard will coincide with heaviest precipitation rates which will likely occur Monday morning. Travel in or below avalanche terrain is not recommended. 

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2–3

    Very dangerous avalanche conditions will exist through the forecast period. Another 1-2ft of new snow by Monday afternoon will bring snow totals since Saturday to 4ft+. This is a prolonged and heavy loading event, and the snowpack needs time to adjust. Avalanches are most likely to fail within new and wind drifted snow, but deeper layers continue to be tested by ongoing precipitation. Very large avalanches could break several feet thick and run full track to valley bottom.

    Expect widespread and reactive slabs and choose simple terrain away from overhead hazard. The largest and most reactive slabs will exist in wind loaded areas and at upper elevations. Human triggered avalanches are very likely on slopes 35 degrees and steeper. Gather information as you travel and carefully assess the snowpack watching for shooting cracks, collapses, and recent avalanches. Only venture out during the storm if you are confident in your ability to identify and avoid avalanche terrain. 

     

    (12/31/20) A recent snowboarder-triggered avalanche that broke 1-2ft deep on a NE aspect at 4900ft. Photo: Jake Little

Avalanche Discussion

Numerous natural and human-triggered avalanches were reported Sunday, the majority of which were small and shallow breaking 4-6in deep within the most recent layers of new and wind drifted snow. Observations above treeline have been limited during this intense multi-day storm cycle where rounds of larger natural avalanche activity likely occurred. The Heather Meadows weather station recorded an impressive 8in of water since the start of the new year (and 11in the past week) bringing snow depths above 4000ft to 10-12ft. Rain below 3500ft caused significant melting of an already shallow low-elevation snowpack. A significant rain event on Friday was followed by cooling temperatures Saturday and Sunday as heavy precipitation continued and over 2ft of new snow accumulated in areas above 4000ft. In addition to very dangerous avalanche conditions, several non-avalanche hazards exist including tree well and deep snow immersion. Find out more information about deep snow safety HERE.

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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