Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 6 years ago.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

Highlights

Storms keep piling up the snow around the WestSouth zone and yet another system will build new weak layers that you can trigger. Seek out lower angled and treed terrain to avoid the storm snow hazard. At this point, any avalanche can grow large and deadly.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2

    Yet another winter storm will impact the region Tuesday night into Wednesday morning building new storm slabs that you can trigger. With so much snow now on the ground, any avalanche may entrain significant snow and grow large enough to bury and kill you. Use patience and give the snowpack time to adjust to all the recent loads. Stay away from all open slopes greater than 35 degrees. You can use small slopes to test the new snow, however, with so many layers in the upper snowpack, they may not tell you everything you need to know. Other deeper weak layers may still exist. As the snow totals continue to increase, so does our uncertainty. Dial it back and seek out simple terrain where you can easily manage the avalanche risk. 

    Near or below the rain-snow line Wednesday, you may find wet and unstable surface snow. If you see new rollerballs or find fresh piles of debris, steer around similar terrain. While getting this deep heavy snow to start moving may prove difficult, once it does, it may gouge and produce large avalanches.

    (1/3/2021) Up track tests like this can highlight weak layers in the new snow. However, the only work as deep as your skis, snowshoes, or machine sinks into the snow. other weak layers could hide deeper.

Avalanche Discussion

This storm should peak overnight for most of the zone and could result in a natural avalanche cycle. Consequently, you’re likely to see the highest avalanche danger in the morning. However, if snow showers or strong winds linger longer than expected, anticipate very dangerous conditions and natural avalanches. This is most likely in locations further south near Mt St Helens and Mt Adams. The latest storm comes as part of a week-long parade that favored the volcanoes. As of Tuesday afternoon, all sites have received significant precipitation (Paradise 9.5”, Crystal 4.8”, White Pass 4.7”) with the snowpack growing by 3-5’. Several potential weaklayers now exist in the snowpack that could fail and produce isolated very large avalanches. While stormy weather limited observations in the West-South, several very large crowns were observed at nearby Snoqualmie Pass. These slides highlight the potential for avalanches to fail deeper in the snowpack and produce destructive slides. 

We are particularly uncertain about areas around Paradise and the other volcanoes where the snow totals have been the highest and observations have been limited. If you travel to these areas please submit a public observation to let us know what you find. 

Two notable snowpack markers exist in the upper snowpack and can help you identify recent storms. On New Years Day a crust was formed and buried in most locations. We believe the majority of the avalanche activity will occur above this thin crust. Deeper in the snow, you should find a thick layer of melt-freeze grains that constitute the 12/21 crust. The vast majority of the snow above this layer fell as part of this ongoing storm cycle. 

In addition to dangerous avalanche conditions, non-avalanche hazards exist including tree well and deep snow immersion. Find out more information about deep snow safety HERE.

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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