Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

Sat
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

The West South will continue to float down an atmospheric river on Friday. High elevation rain, gusty winds, and generally stormy weather will result in dangerous avalanche conditions around the zone. Consider staying out of avalanche terrain until this river has dried up.

Avalanche problems

  • Wet Slabs

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

    Continued high-elevation rain around the zone should result in snow ripe for wet avalanches on Friday. You could see loose avalanches failing from a point and fanning out as they descend, or slabs failing as water percolates the snowpack. Larger chunks of snow could break off sagging cornices or shed from rocky ledges. These sporadic and difficult to forecast avalanche problems aren’t the type to try to tiptoe around. Your best mitigation tool is to avoid anywhere an avalanche can start, run, or stop until this atmospheric river wraps up.

    (12/23/2022)

    A wet slab avalanche at Mount Rainier National Park from our previous atmospheric river event over Christmas. Similar avalanches are expected during this event.

    Photo: NPS Rainier Rangers

Avalanche Discussion

We’ll keep rollin’ on the river in the West South on Friday. Rain is expected to continue up to around 7000 feet in elevation for much of the day before a slight cooling trend takes hold overnight. It likely won’t be a very pleasant day in the mountains, but we dropped the hazard level since the initial onset of rain on snow has already occurred. This means that the first wave of natural avalanches has likely passed, but the snowpack should now be primed for more human-triggered slides and less widespread natural activity. 

We have very limited information from Thursday due to the obviously poor conditions. Crystal Mountain Pro Patrol reported that some large natural avalanches occurred, but their size and character were not confirmed due to poor visibility. At upper elevations, this event started as snow before temperatures crept up and changed precipitation over to rain. NWAC weather stations at Paradise and Crystal Mountain have both recorded close to 1.75 inches of water as of Thursday afternoon, with White Pass and Mount St. Helens recording significantly less. We anticipate another 1+ inches of rain to impact many areas of the zone before this storm starts to taper and cool.

With a few layers of interest found in the snowpack prior to this storm, we could continue to peel back the snowpack onion layer by layer as we strip down toward the Christmas Crust. Again, even though the hazard has dropped due to natural avalanche likelihood, it will still be a dangerous day to be in the mountains and likely an unpleasant one at that. There's a chance that we haven't seen the worst of it yet. You may want to consider waiting this storm out. But if you decide to enter the mountains, it’s been said that people on the river are happy to give. So give us some observations and pictures of what you’re seeing out there and make conservative terrain choices.

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