Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Precipitation amounts and temperatures are dropping Thursday, and there will probably be a few inches of snow at upper elevations. Wet snow problems linger, so avoid steep terrain and don't travel on slopes beneath large cornices or glide cracks. Similarly, if new snow drifts grow larger than about 6 inches at upper elevations, avoid steep slopes with these thicker drifts. 

Avalanche problems

  • Glide Cracks

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

    Your main concern is glide avalanches peeling off either steep rock faces or surfaces with low vegetation like shrubbery and grass. Soggy cornices could still shed as well. Other wet avalanche types have probably already run their course but are not completely out of the question. 

    During your outing on Thursday, avoid traveling beneath slopes where you see glide cracks or large cornices above you. Continue to avoid steep slopes. If you have any doubt or see any natural activity, steer clear of avalanche terrain. 

    Example photo: Glide avalanche on the south side of Herman. This rock slab frequently produces avalanches during periods of warming and also during rain events.

  • Wind Slabs

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

    6-10 inches of snow may fall near the top of our upper elevation band. Snowfall depths will probably be closer to 2 inches at the bottom of the upper elevation band by the end of the day. If you make it up high, you might be able to trigger a small avalanche in deeper wind-drifted pockets of snow. We're not sure how the new snow will bond to the previously wet old snow surface. Precipitation is expected to continue as temperatures drop, so we suspect that the layer will bond fairly well and the previously wet underlying layer will slowly freeze.

    Search for actively blowing snow and featured surfaces to identify drifting. Up high, drifts may be a foot deep, but many will probably be shallower. Moderate wind is forecasted, so some surfaces may be scoured back to a crust of the old snow surface.  You can easily dig shallow hand pits to identify any weaknesses in the new snow layer, or see how the new snow is bonding to the underlying layer. If your weight causes long, shooting cracks, or where you identify thicker drifts, continue to follow the advice of avoiding steep slopes.

     

    Example photo: A small, shallow, human triggered wind slab avalanche, similar to what you might be able to trigger on Thursday. 

Avalanche Discussion

Freezing temperatures at upper elevations will slow the wet snow avalanche problems up high.  They won't be completely off the table for a few days while the water still drains through the snowpack. 

Our last reports of large and very large natural wet avalanches were from the weekend. We suspect most natural wet avalanche activity has backed off, but considering how much water we've received at such warm temperatures in the last few days, it wouldn't be too much of a surprise if a large natural avalanche still released as the snowpack drains. The problem is, although natural activity is trending unlikely, you never know when or where one may occur. Any lingering avalanche activity will likely happen at mid or upper elevations where there's still several feet of snow base.

We've seen about 7.5  inches of rain in the West North zone since temperatures soarded.  Travel will go from sticky, soggy, and punchy, but up high as temperatures cool you might encounter hard, frozen surfaces. Snow cover is thin everywhere, but especially at lower elevations, for the first day of February. Snowpacks are averaging around 50% of what we normally see at this time of year. Creeks are swollen and there's snow lacking in many areas of the lower elevation band.  At most elevations, heavy wet snow, runneled surfaces, running water, exposed rocks/dirt, and avalanche debris now litter the landscape, making for challenging travel conditions. At higher elevations, you might encounter harder surfaces. 

Regions covered