Avalanche forecast

Olympics

Northwest Avalanche Center
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Avalanche danger

Sun
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

You can still find wind drifts in exposed terrain and if you find one 6" or deeper, there's a good chance you can trigger it on a steep slope. Active transport, cracking snow surfaces, and easy hand shears within the shallow snow will be the best clues to identify and steer around the problem areas on Saturday.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    You might find 4-6" of settled snow above the 2/13 crust on Saturday. Any new snow will help form fresh drifts because by late Thursday much of the snow available for transport had already been redistributed by gusty and swirling winds easily. Slabs have been forming atop a faceting old snow interface and in isolated areas on an icy 2/13 crust.  A small natural wind slab below a corniced ridgeline (a frequent flyer) highlights the potentially touchy nature of these fresh slabs on Thursday. Alpine bowls and below corniced ridgelines are where you're most likely to find a slab you can trigger. Slabs that formed Thursday may have been partially neutralized on sun-exposed aspects by sunny skies on Friday. Therefore, shaded aspects and high-elevation slopes will be the most likely places to find a pocket that could take you for a ride.

    (2/16/2023)

    Small natural wind slab in center of photo. North Bowl, N aspect at 5200 ft.

    Photo: Sam Siemens-Luthy

Avalanche Discussion

Friday was a sunny day on the Ridge and we're expecting a dusting to an inch of snow over the next 24 hours to maintain some hazard in wind-exposed terrain.

On Thursday, professional observers found 4-5" of low-density, right-side-up, and faceting snow sits above the 2/13 crust complex.  Winds were effectively redistributing the snow (see video) into drifts up to 15" deep, while isolated slopes were scoured to ice. Ridgelines were scoured bare in many places while trees had lost most of their snow. The 2/13 crust complex has a breakable 1 cm upper crust, 2 cm of faceting dense snow, and a 2 cm fully supportable lower crust.  This faceted sandwich could come into play in a future loading event. The 2/3 crust/facet interface sits 35 inches or more below the snow surface. Avalanche professionals continue to get some reactivity in test results under this crust, but it is not currently a concern for human-triggered avalanches given the thickness of the 2/13 crusts.

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