Lawinenlagebericht

West Slopes South

Northwest Avalanche Center
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Lawinengefahr

Sun
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
3 · Erheblich
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Kernpunkte

A long stretch of warm and sunny weather may push the snowpack past its breaking point on Saturday. You could see natural wet avalanches on any steep and rocky slope. Plan to travel and return early before the snow turns to mush and the danger peaks. 

Lawinenprobleme

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2

    After three nights of above-freezing temperatures, the upper snowpack may finally shift past its tipping point and become wet and unstable. Natural wet avalanches may occur on any aspect. Some of these slides may entrain significant amounts of snow, grow large, and gouge into older layers. Pay attention to the terrain above you. When you start to see snow shedding from rocks or smaller loose slides, it’s time to go somewhere else. Choose routes that allow you plenty of options to limit the time you spend underneath large and complex avalanche terrain. 

    While we’re primarily worried about large natural avalanches, you may trigger loose slides on any slope greater than 35 degrees. It won’t take long for whatever thin crust that forms overnight to break down in the warm and sunny weather. Once you start sinking into the snow past your ankle, you can trigger loose wet avalanches. Find lower-angled or slightly firmer slopes.

    (3/28/2021) Example: Loose wet avalanches on a NE aspect in the Tatoosh range earlier this winter.

Avalanche Discussion

Considerable danger combined with loose wet avalanches can at first glance seem rather common. However, we’re talking about the possibility of the first widespread spring shed cycle of the year. Weather stations all across the zone remained above freezing for the past 3 or 4 nights. Temperatures on Saturday could easily reach into the 50s and even 60s. And, without the cooling breeze, the full effect of the heat and sunshine will impact the snow. These are all clear red flags that point towards dangerous avalanche conditions. 

You could encounter any number of springtime “shed” avalanches. Washington State DOT crews triggered shallow wet slabs with explosives this week while working on the Chinook Pass opening. These avalanches highlight the potential for water to pool on deeper layers in the snowpack including the very deep mid-January crust. Glide cracks formed on many smooth slopes during the recent warm weather. These slabs could release without warning any time of the day or night. Similarly, large and overhung cornices have begun to sag and could fail. All of these springtime hazards should be on your mind. Fortunately, the travel advice for all of them is the same. Plan to travel and return early before the heat of the day brings the most dangerous conditions. Give yourself plenty of options to adapt to the rapidly changing conditions. This includes making sure you have a safe route back to the trailhead. Pay attention to the slopes above you. They may warm faster than where you travel. Choose routes that help limit the time you need to spend underneath large and rocky avalanche slopes. 

Daily avalanche forecasts will end on Sunday, April 18th.

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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