Avalanche forecast

Olympics

Northwest Avalanche Center
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Avalanche danger

Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Your likelihood of triggering a large slab avalanche is decreasing, but the consequences remain severe at upper elevations. Ascend cautiously as you approach ridgelines and above treeline terrain, navigating around steep rollovers and wind-loaded lee slopes.  Sunshine on Monday could destabilize dry surface snow on southerly aspects to form small Wet Loose avalanches, so prepare to adjust your aspect.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Wind slabs are healing slowly, but they it's not yet time to let down your guard. Friday night and Saturday's storm brought around 10" of snow, with 14" of snow now sitting on the 12/21 crust. Sustained moderate winds at ridgeline during the storm blew that snow around to create large slabs and cornices on N aspects. You can still trigger on specific terrain features such as 35 degree or steep slopes below recently formed cornices and on convex rollovers.  Recent snow arrived with less wind, so your typical visual clues may be less useful. Dial back your terrain selection where you find a thin crust more than 12" below the surface, or a thicker crust more than 14" below the surface. These depth gauges will help you identify wind loading. Firm or punchy snow beneath the top few inches of snow could also be a good indicator. Whumphing or cracking of the snow also provides a quick indicator that you are heading into wind-affected and unstable snow. 

    Cornices are a relatively novel concern for the Olympics this season. Practice save travel and avoid traveling under corniced slopes, which are the same ones you should avoid due to their wind loading.

    (12/27/2020) Wind-slab example from an adjacent zone, releasing on a wind-loaded slope below fresh cornices.

Avalanche Discussion

Several inches of new snow fell on Monday with light winds E/SE and S winds and gradually increasing temperatures causing the snow line to rise to around 4500 ft. The warming temperatures initiated some small rollerballs and point releases in the 4500 ft to 5000 ft range.

The heavier, denser snow falling Sunday likely limited the potential for Wet Loose avalanches. However, they may still be possible to trigger at upper elevations given the warm temperatures. Tree bombs and rollerballs will give you the signal that slopes are heating up and it's time to adjust your aspect away from the sunshine.

Professionals on Sunday found 14" of snow that was generally right-side-up and bonding.  Professionals noted some reactivity above and below the stout 12/21 crust. This crust may provide a bed surface for any large avalanches. In areas where there is a firm slab, it could propagate widely and fracture above well above you on the slope. The crust limits our avalanche concerns to the snow that fell since 12/21. A minor crust may be found a few inches above the more obvious one.

Thin snow coverage still exists along ridgelines and at lower elevations. Give yourself extra time to deal with these travel challenges. 

2020-21 Forecast Schedule: Avalanche danger ratings will be issued for the Olympics every Friday through Sunday and during mid-week holidays. During the week when the Hurricane Ridge road is closed, forecast information will be updated daily to include expected conditions and relevant travel advice under the No Rating label.   

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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