Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

The snowpack may change from wet and sticky to dry and wintery as you ascend in elevation Saturday. While some of these slides could be tough to trigger, if they get rolling they could easily grow large and consequential. Be leery of steep slopes over 35 degrees, especially if you see any other signs of unstable snow.

Avalanche problems

  • Storm Slabs

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

    This recent warm storm may have left a heavier and firmer slab over weaker drier snow below. You’re most likely to trigger an avalanche failing at the base of the new snow on convex rollovers, in unsupported terrain, and in wind-loaded pockets. Small slopes, uptrack tests, and hand pits can all give you an idea of how the recent snow may respond. If you see it crack, fail in slab-like blocks, or slide easily, then you’ve found the storm slab issue. 

    The size of these potential avalanches really depends on your location. Expect the largest slides near the volcanoes and at higher elevations. Even though these slabs may seem sluggish and hard to trigger, these dense avalanches could entrain quite a bit of snow, grow large, and descend far.

    (4/7/2023) Convex test slopes produced shooting cracks like this failing at the base of the new snow. Photo: Dallas Glass

  • Loose Wet

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

    It should be pretty easy to find wet and punchy snow Saturday. In some locations, you may still trigger loose wet slides. If you start to see new rollerballs or find that when you push on a small test slope the surface snow accelerates, then the scales are tipping. Stay off of nearby slopes greater than 35 degrees. Periods of rain, sunshine, and greenhousing could all make the snow surface quickly go from just wet and mushy to unstable and scary. 

    We aren’t expecting much in the way of natural wet avalanches. However, snow may shed from rocky faces and trigger slides below. Look for routes that help limit the time you spend under rocky complex terrain.

    (4/7/2023) Piles of rollerballs like this indicate the snow surface is becoming wet and unstable. Photo: Dallas Glass

Avalanche Discussion

A bit of a lull in the weather Saturday should bring less rain, more clouds, and mild temperatures. In general, this will help the snowpack. However, transition days like this can be complicated. Signs of unstable snow start to decrease, but the storm really just ended. 

Over the past several days warm and wet weather took aim at the West South zone. Precipitation totals varied widely across the zone. Mt St Helens recorded more than 2.5 inches of water while White Pass saw less than 1/2 an inch. In general, most sites received between 1-1.5 inches of precipitation. Snow levels reached high up the mountain sides and topped out between 5500 and 6000 feet in most areas. 

On Friday, an NWAC forecaster near Crystal Mt found wet snow to nearly 6500 ft that produced piles of large rollerballs and a few small loose wet slides. The storm snow also cracked and failed on small slope and uptrack tests above the rain-snow line. Amazingly,  below the relatively warm surface, the snowpack is still very cold, dry, and layered. 

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