Avalanche forecast

Stevens Pass

Dec 11 – 12, 2018Northwest Avalanche Center
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Archived · expired 8 years ago

Avalanche danger

Thu
Alpine
4 · High
Treeline
3 · Considerable
Below
3 · Considerable

Highlights

We have received significant snowfall, strong winds, and have a weak snowpack. This is a recipe for avalanches. It is not the time to travel in areas where avalanches can start, nor linger where they can run or stop.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1

    Moderate to strong Southwesterly winds are expected to accompany the cold front as it passes overnight into the morning of the 12th. These will create thick, dense slabs on leeward slopes and features. Some of these slabs are sitting on old weak snow, and may surprise you by breaking well upslope. As a result, it is best to avoid steep, wind drifted terrain today.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1

    Storm totals from the 11th and 12th are expected to be substantial. The deep new snow is not bonding well to the old snow surface, which is weak and faceted. During the day on the 11th, professional observers reported natural, and remotely triggered avalanches on the old snow layer on a variety of aspects and as low as 4700ft. You are likely to trigger an avalanche that will break on the interface of the new and old snow on all aspects. Expect shooting cracks through the snow, collapses, and avalanches that break widely over terrain features. It will be prudent to avoid avalanche terrain today. 

Snowpack Discussion

Coming soon.

Regions covered