Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Though not a big storm, there’s plenty of new snow to pose a danger in certain types of terrain. Look for newly wind drifted areas and avoid pillow-like slabs on steep slopes. If the sun comes out, you could see natural wet avalanches quickly develop especially near rocky features.

Avalanche problems

  • Wind Slabs

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

    While the snow from this storm might not be exceptionally deep, the winds have been quite strong. As a result, you’ll want to watch for and avoid freshly forming wind slabs. Look for blowing snow, sharp drifts, and textured surfaces to help you anticipate wind-loaded areas. Because of the southerly and easterly nature of the recent winds, don’t be surprised to see wind-affected snow on slopes you normally consider safe. 

    The newly forming wind slabs are the biggest concern because they will be the easiest to trigger. However, don’t forget about wind-loaded areas from earlier this week. These older and possibly more dangerous slides could break deeper into the snowpack and grow much larger. To make it more complicated, the new snow may even hide these older slabs from view. Look for large clues like old drifts or the firmer feel of the underlying snow to help anticipate where these bigger wind slabs may still linger. You can always seek out less wind-affected or lower angled snow to avoid this avalanche problem.

    (4/11/2022) Example: These wind-clues are from an easterly wind event just a few weeks ago and show an unusual loading pattern. Photo: Dallas Glass

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    This avalanche problem depends entirely on the sky. If it stays cloudy, you likely won’t have a loose wet issue. However, with a decent bit of new snow on the ground, if the sun comes out, expect loose wet avalanches. Pay attention to the weather. If you start to notice the sunshine, odds are, so is the snowpack. Rollerballs and small piles of fan-shaped debris also serve as great clues. If you find these conditions developing, consider routes that help keep you away from steep sunny slopes. While most of these slides should stay relatively small, some of them could entrain enough snow to run further downhill. Don’t let them push you off a cliff or into a creek.

    (4/17/2022)

    Example: This rollerball occurred during sunny weather with fresh snow earlier this week. 

    Photo: Dallas Glass

Avalanche Discussion

As of Wednesday afternoon, this storm has brought 4-6” of snow to the West South zone and counting. By Thursday evening, storm totals could easily exceed a foot in some areas. Because of the relatively warm temperatures, steady freezing levels, and light precipitation rates, we expect the new snow to settle quickly. However, if you find more than 10 inches of snow, don’t rule out a possible slab even in wind-sheltered terrain. These storm slabs would be most likely on a very steep or unsupported slope. 

This storm adds to the snow over the 4/18 interface. In most locations, the base of these storms is marked by a melt-freeze crust. You can use this interface to help focus your observations on the recent snow, where we believe most avalanches will occur. We are still keeping an eye on the remainder of the upper snowpack above the 4/8 crust. This prominent snowpack marker is often found about 2.5-4 ft below the surface all across the zone.

Regions covered