Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

The warm and sunny weather may cause the snow surface to become wet and unstable Tuesday. When you find a sticky and/or punchy surface start to seek out shadier and more frozen terrain. Make sure to give yourself plenty of options during the day to adapt to the dynamic and changing springtime conditions.

Avalanche problems

  • Loose Wet

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

    The sun will need a little bit of time to thaw the snow surface on Tuesday before you begin to worry about loose wet avalanches. If you encounter a thin/weak refreeze in the morning, this shift could occur quickly. When it does, you may find a wet, sticky, and/or punchy surface. Use your boot to monitor the changing snow conditions. When you begin to sink near or past your boot top, it’s time to find somewhere more frozen or lower angled to travel. The snow will soften first on east-facing slopes. As the day continues to warm unstable snow may spread to other aspects and higher elevations. In some areas, the upper snowpack consists of layers so weak wet snow that loose avalanches may entrain allowing them to grow larger and run farther.

    (4/4/2021) Take the time to step off your mode of travel and see how deeply you are sinking into the moist snow. If you're sinking in deeper than your ankle, you should start to suspect wet avalanches. [Boot Pen: 40cm N ~4600']

Avalanche Discussion

We haven’t really seen a spring-time shed cycle yet in the West South zone. On Monday, White Pass Ski Patrol reported a very large natural avalanche on an ESE aspect of Coal Creek Ridge (Goat Rocks Wilderness). This may be the warning shot indicating the snowpack is primed and ready to start falling down. In nearby Snoqualmie Pass, numerous glide/shed avalanches occurred Friday-Sunday at lower and mid-elevations. These recent events, combined with Tuesday’s warming temperatures, has our attention. Could this be the day we see large natural avalanches? Since predicting glide/shed avalanches is so challenging, avoidance is the best strategy. Choose routes that limit the time you spend below steep rocky terrain, slopes where you see crevasse-like glide cracks, and drooping cornices. Make sure you can easily adapt to the dynamic spring conditions, especially as you head back towards the trailhead in the afternoon. 

This forecast hinges on the overnight freeze and Tuesday’s cloud cover. A poor freeze and full sunshine could lead to more dangerous conditions than expected. One thing’s for sure, you’ll see the lowest danger first thing in the morning. As temperatures rise and the sun moves higher in the sky, expect the hazard to increase quickly. At lower elevations and on more southerly aspects, the upper snowpack underwent several melt-freeze cycles this month resulting in wet and sometimes weak snow. On more shaded aspects and higher in the terrain, a cold dry winter-like snowpack exists just below the surface. Even though recent weather felt like spring, the snow has not yet made its transition. Don’t let the nice weather fool you, and give the snowpack time and space to adapt to the changing conditions. 

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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