Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Warm and sunny weather will make Sunday the warmest day of the year creating plenty of weak snow surfaces. Plan to travel and return early. Choose routes that limit the amount of time you spend underneath large and complex slopes.

Avalanche problems

  • Loose Wet

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

    After another night of above freezing temperatures, large natural avalanches may occur Sunday. These won’t be small loose wet slides. Avalanches may entrain significant amounts of wet heavy snow, gouge into older layers, and travel far downslope. Pay attention to small signs that the snowpack is primed and ready. Snow shedding from rocks and small point-release slides can serve as clues before these larger events unfold. Pay attention to the slopes above you, and limit the time you spend traveling in and underneath large avalanche paths. 

    While the primary concern stems from large natural avalanches, you may trigger wet slides on slopes greater than 35 degrees. Any thin crust that forms overnight won’t last long in the hot and sunny weather. Once you punch into the snow past your ankle, it’s time to change locations. Find lower angled or slightly more frozen snow to avoid triggering a loose wet slide.

    (4/15/2021) When you find a wet, sticky, and punchy snow surface like this you may trigger loose wet avalanches on similar slopes. New rollerballs are also present on the slope.

Avalanche Discussion

While the West-South zone has experienced warm temperatures recently, moderate to strong easterly winds have helped limit the pooling of water at the snow surface. This is no longer the case as the winds have calmed and temperatures will reach the highest of the season on Sunday. Locations on Mt Rainier and Mt St Helens experienced are now experiencing the 4th day with poor overnight freezes. Consequently, you could encounter locally more dangerous conditions in these areas with larger and more abundant natural avalanches. 

Predicting the timing of these spring-time avalanche cycles is tricky. Small to large natural wet avalanches were observed Saturday and should be likely again Sunday. Pay attention to the terrain above you. Choose routes that reduce the amount of time you spend below rocky faces, slopes with crevasse-like glide cracks, and overhanging cornices. As temperatures warm up, snow tends to fall down. Make sure your travel plans leave you with plenty of options to reduce your exposure and change plans if you begin to see more natural avalanche activity than expected. 

This is the final full avalanche forecast product of the 2020-21 season. As our capacity thins during the warmer months, please continue to share your observations and make use of our mountain weather forecasts (daily through the end of April). From all the forecasters at NWAC, thank you for all your support that makes this product possible and we look forward to resuming full operations in late 2021.

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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