Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

The West-South zone should demonstrate it’s variability Wednesday with cooler and windier conditions near the Cascade crest and hotter weather close to the Volcanoes. This could drive your primary avalanche concerns. Steer away from steep slopes below fresh cornices and where you find firm hollow sounding snow.

Avalanche problems

  • Wind Slabs

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

    You could see two types of wind slabs in different locations Wednesday. On N-SE aspects, look for older harder to trigger wind deposits. These formed during Monday’s extreme winds and could reside well below ridgeline and along the sides of mid-slope features. When you see old large drifts or feel firm hollow snow, steer around nearby steep slopes and convex rollovers. New, softer, and easier to trigger wind slabs could form Tuesday night and Wednesday with strong easterly winds, particularly near Crystal, White Pass, and sites close to the Cascade Crest. Watch for blowing snow and smooth pillow-like drifts near ridgecrest on SW-NE aspects. These are the same slopes often stripped during most storms. Travel around these newly forming slabs.

    (11/28/2020) Textured surfaces like this indicate wind loading on nearby slopes.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    In areas where the warm air from the west takes hold, you could see small loose avalanches naturally occurring. You’re most likely to encounter loose wet slides near the volcanoes and other sites away from the Cascade crest and the cooling east breeze. Many of the snow surfaces are pretty firm and beat up from Monday’s storm. Consequently, it may take the sun and warm weather longer than normal to soften the snow. Clues such as new rollerballs and the snow shedding from rocks can serve as indicators that you can trigger loose wet avalanches. When you see these signs, seek out shaded terrain.

    (11/26/2020) Pinwheels at Mt. Rainier after rising freezing levels and the sun came out a few days after a storm. [S aspect 5400']

Avalanche Discussion

If Wednesday is a battle between the cold east wind and the hot westerly air, how do you know which you’re dealing with? Let your clothing guide you. When you stop, if you find yourself reaching for another coat in the cold breeze, you should think about new wind slabs. Put loose wet avalanches on your mind if you question the date on the calendar, find you don’t have any jackets left to take off, or regret the choice of wearing long-johns. 

In general, the snowpack around the West-South is deep and strong (3-6’, 90-180cm). We expect avalanche activity to occur within the recent snow or at the newest interface (11/30). On Sunday, surface hoar was reported in the Tattoosh, Crystal, and White Pass areas prior to the storm. We don’t know if this weak feathery snow survived. If it did you could see avalanches break wider than expected or trigger remotely. If you dig in the snow on shaded sheltered areas, please let us know what you find by submitting a public observation.

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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