Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

Sun
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Large and dangerous wet snow avalanches are likely as temperatures continue to increase. Very large glide avalanches are becoming more frequent, and wet loose avalanches are entraining  more snow than you might normall expect. Pay close attention to snow surfaces, and when they begin to soften start thinking about moving to low angle areas away from overhead hazards, as they  become unsupportable very quickly in this intense sun.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2

    Wet loose avalanches are becoming easy to trigger, and natural avalanches will grow larger as freezing levels increase to 10,000ft on Saturday. These unseasonably warm temperatures which have not dipped for days are beginning to take a toll on the snowpack. The avalanches will continue to entrain more snow, and could become larger than what you normally think of when you see “wet loose avalanches” as a problem in the avalanche forecast. Take this into account as you travel on Saturday. 

    Conditions change very quickly, and a slope that was firm an hour or two ago may hold 6 inches of loose, unconsolidated snow on the surface, enough to slide if steep enough. Avoid steep slopes on Saturday, paying attention to where the sun is in the sky and which slopes are getting soft. The progression of softening snow moves from east in the morning, around south, then west in the afternoon. This is normally the guidelines to follow for slopes to avoid at certain times of day, but temperatures warmed so much that even north facing slopes are avalanching. Hold a large margin for error on where you travel. Large avalanches will run far, so do not linger on the lower angle slopes beneath them either. 

    (4/16/2021) A large natural wet loose avalanche which occurred in the last 24 hours in the West North zone at 5000ft.

  • Glide Cracks

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

    As mentioned above, these unseasonably warm temperatures are beginning to take a toll on the snowpack. Glide avalanches are becoming a large concern. A backcountry group on Whitehorse Friday observed a very large glide avalanche failing at sunrise on a northwest aspect at 3800 feet. The party heard it crashing down the valley for minutes, and were unsurprised to find that it ran full path upon their descent.  Another one was seen on Kyes Peak near Monte Cristo.  Be very cautious around glide cracks as temperatures soar.  If you see any, avoid traveling on slopes beneath them, as they are ripe for failure. They are very unpredictable and now is not the time to push your luck with traveling beneath them.

    (4/16/2021) Large glide cracks, compressions and a glide avalanche on a north aspect at 4400ft in the northern Mountain Loop Highway area. Photo: Steve Kuznetzov

Avalanche Discussion

Uncertainty exists as to when the larger avalanche cycle will begin, but as temperatures peak over the weekend expect to encounter more dangerous avalanches. Keep your return routes in mind - slopes you crossed safely early in the day may become wet, weak, and dangerous by afternoon. Don’t wait until it’s too late and avalanches start coming down all around you that you decide it’s time to retreat. When you start seeing signs of a weakening snowpack such as easily punching down several inches, or noticing any nearby avalanches, leave the area for lower angle terrain or firmer snow.

Wet loose and glide avalanches top our list of concerns, but stay alert for wet slab avalanches as there’s chances that saturation in the upper snowpack may weaken an interface near the surface. Cornices will melt out and sag more in this springlike weather, causing an increase in failures of these huge features. Limit your time beneath them and don't stand near their edge.  These are additional reasons to travel very carefully in the backcountry this weekend, as rapid prolonged warming tends to cause difficult-to-predict conditions.  

Daily avalanche forecasts will end on Sunday April 18th.

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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