Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

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

You may encounter a few small pockets of wind drifted snow, particularly on higher elevation shades slopes. Don’t let one of these smooth pillow-like slabs catch you off guard in consequential terrain. A major storm is on deck for Sunday night and will cause avalanche danger to quickly rise.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    You may find a few shallow wind slabs across the higher terrain of the West South zone Sunday. Fortunately, most of these potential avalanches will be so small that they won’t pose much of a risk. So, don’t let one of them surprise you if you’re traveling in high consequence terrain. Look for blowing snow, textured surfaces, and sharp drifts to help anticipate which features may hold wind-loaded snow. When in doubt, seek out lower angled or less wind-affected snow to avoid triggering one of these shallow slabs. 

    Near the volcanoes, additional snowfall and increasing winds may only add to this problem later in the day. In these locations, you could find wind slabs 6-8” deep in the afternoon. This might be enough to knock you off your feet.

    (4/2/2022) A small test slopes produced this 4-8" deep wind slab pocket. Simlar test slopes produced other very small slabs. SE, 6300'. Photo: Dallas Glass

Avalanche Discussion

Locations across the West South zone received 1-3 inches of snow Friday night and Saturday morning. This little storm added to slightly large totals from earlier in the week. Given the recent spring-like weather, it’s no surprise that the sun and warm temperatures quickly affected all this recent snow on most aspects. Rollerballs and small loose wet avalanches were common. On these same slopes, much of the new snow quickly began to incorporate into the underlying spring-like snowpack. In more northerly terrain, the snow surface remained much drier and generally well bonded to the underlying 3/30 crust. 

In the Crystal Mt backcountry on Saturday, an NWAC forecaster found 1-3” of snow over the crust on all aspects. By mid-day, the snow on more southerly slopes was already undergoing a melt-freeze process. A few isolated pockets of wind drifted snow were also observed. These thin slabs cracked and produced very small avalanches on wind-loaded test slopes. 

Two interesting observations came in this week of larger avalanches in the Tatoosh Range (3/30) and on Mt St Helens (4/1). In both instances, these deeper slab avalanches were likely triggered by a cornice fall or other avalanche from above. It's possible that these slides failed on the weak layer created by what’s left of the 3/8 facets and Early March Crust. An NWAC Forecaster was still able to identify the remnants of this layer on Saturday near Crystal. While it is highly unlikely a backcountry traveler would trigger one of these slides, it may still be possible with very large loads like cornices or other slides to cause them to fail.

At lower elevations, the snowpack continues to shrink. Bare ground, open creeks, and punchy wet snow are common.

A major winter storm is forecasted to impact the Cascades late Sunday evening bringing heavy precipitation, strong winds, and fluctuating freezing levels. This will cause the avalanche danger to rapidly rise Sunday night. This isn’t a storm you want to be caught out in accidentally. Make sure you are safely out of the mountains before it arrives.

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