Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Assume borderline high danger to start the day as torrential rains move through the snowpack. Bedrock faces, poorly supported features, and cornices are the most likely to fail without warning, particularly early in the day. Continue to avoid all steep, open slopes where you could trigger a wet avalanche until snow surfaces become supportable.

Avalanche problems

  • Glide Cracks

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2

    We're expecting a significant natural avalanche cycle Tuesday night and there is uncertainty as to when exactly that cycle will end as the rain tapers off early Wednesday. Rainwater will continue to drain through the snowpack, lubricate bedrock slopes, and sagging cornices may continue to fail without warning. The risk of large natural avalanches remains possible early in the day, while human-triggered wet avalanches will be likely. Cooling temperatures will gradually decrease the danger as drainage channels form rills on the snow surface, indicating a stabilizing trend. 

    Put a margin for safety between yourself and anywhere snow looks precarious. Smooth bedrock faces are of greatest concern. These may have re-loaded with 2-4 feet of snow following the glide cycle earlier in the season. You might see a brown frown tipping you off to the potential problem. Cornices will be drooping and heavy. These could easily fail and trigger wet avalanches on the slopes below. There's also a slight possibility that water pools on the 12/7 crust, forming a wet slab.

    Keep it simple and don't spend time on or under steep open or poorly supported slopes.

     

    Example: A glide avalanche exposing a smooth bedrock face that will likely have running water on it on Wednesday.

     

    Photo: Jared Drapala - Baker Mountain Guides

Avalanche Discussion

Heavy snow continued above 4000 ft in the Baker area on Tuesday with a changeover to rain at lower elevations. Very heavy precipitation should continue Tuesday night with a changeover to rain instigating a widespread natural avalanche cycle as snow levels rise to around 7000 ft. Snow levels should lower rapidly as precipitation mostly ends early Wednesday, but some rain and snow showers could continue. Moderate winds may help refreeze the snow surfaces first at upper elevations, enabling instability to persist longer at lower elevations. Make sure you have a refreezing crust or a well drained upper snowpack (with rain rills) before engaging with open slopes steeper than 35 degrees on Wednesday. And remember that rain is unlikely to fall above NWAC forecast elevations, so the risk of isolated very large avalanches running from these elevations down to valley bottoms will linger well into the morning hours.

Avalanche activity has been reported over the last several days. A widely propagating shallow storm slab was reported in lower elevation terrain in the Baker Backcountry on Tuesday (see photo in gallery). Monday also featured a variety of slab avalanches. Some were small, shallow slabs in the topmost layer of new snow (obs, obs), others were a bit bigger and deeper (obs, obs). The structure creating these avalanches will likely wet with the heavy rainfall expected Tuesday night.

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