Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 6 months ago.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

Highlights

A weak snowpack structure, atypical of the Washington Cascades, is well documented in the West South zone. Avalanche activity has been constant on these layers throughout the week and shows no signs of slowing down. Make trip plans that limit or eliminate your exposure to slopes steeper than 30 degrees.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–2.5

    You need to continue to make travel plans that account for persistent weak layers in the upper snowpack. Since Saturday, we have had documented persistent slab activity in our zone daily. Red flags such as long shooting cracks, whumpfing collapses, and widely breaking avalanches are all signs that the snowpack is unhappy and showing its teeth. 

    On Friday, this trend is expected to continue. Windy conditions may exacerbate the problem. Slabs could become thicker and potentially more reactive as snow is transported onto leeward slopes. Yes - you'll want to avoid these wind-loaded areas where it's possible to trigger a wind slab avalanche. But these are the same areas where persistent grains deeper in the snowpack could result in widely breaking or remotely triggered slides.

    The usual tips and tricks won't work to help identify areas with a persistent slab. Uptrack tests, small test slopes, and even hand pits can't give you a sense for where or how these weak layers will fail. Your best management technique will be to avoid all open slopes over 30 degrees. That includes wind-loaded terrain and even large openings in treed areas. 

    (2/24/2026)

    A widely breaking natural avalanche in closed terrain at Crystal Mountain. This one broke roughly 800 feet wide and was 2.5 feet deep, failing on the 2/13 surface hoar.

    Photo: Crystal Mountain Pro Patrol

Avalanche Discussion

On Thursday, NWAC forecasters traveled to White Pass to gather more information on our persistent weak layers - the 2/13 surface hoar, and 2/7 crust with facets. They found a very similar snowpack structure to what has been identified near Crystal Mountain - weak and spooky! Snowpack tests in both of these areas continue to produce concerning results. Instead of getting better as we distance ourselves from last weekend's storm, they've actually gotten worse. Add it to the list of irregularities we've experienced this season, along with our current snowpack structure.

Near Crystal Mountain, avalanche professionals spotted more natural avalanches on Thursday, some in areas that rarely produce them. And winds were easily transporting snow on the volcanoes and near the crest, building thicker and stiffer slabs over all of that weak snow.

On Friday, you can expect a very similar day to Thursday, weather-wise.  Breezy conditions and clouds are forecast throughout the zone. The difference will be the slight warming trend. You may even see a few sun breaks in the afternoon. This will add a new layer of uncertainty to an already unsettling time. On Tuesday, we saw a spike in natural avalanche activity despite only a slight bump in temperatures. Will that be the case again? Hard to say, but it's certainly a possibility. At a minimum, you may see new rollerballs or small wet loose slides if it gets warm enough. Even a manageable wet loose could become a problem with this snowpack setup, stressing weak layers and resulting in slab avalanches. Choose terrain carefully and remember that all steep slopes are currently suspect.

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