Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

A warm sunny Wednesday could keep you managing small avalanche issues in wind-loaded and steep sunny terrain. Think about the consequences of the slopes below you. Don’t let one of these smaller slides take you for an unwanted ride.

Avalanche problems

  • Loose Wet

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

    A cold clear night should let the snow surface freeze. So, the sun and warm weather will need to break a new surface crust down before you will have to worry about loose wet slides. If the snow is frozen solid, expect generally safe conditions. Once you start to punch through the surface or see new rollerballs, think about loose wet avalanches. 

    While you could see a few new natural slides near cliffs and rocks, you’re most likely to trigger one of these avalanches on steep sunny slopes where you encounter more than 4-6 in (10-15cm) of wet heavy snow. Fortunately, these slides should remain small, but don’t let them push you into a creek of over a cliff.

    (3/21/2023) The recent loose wet activity was largely confined to steep rocky faces that receive direct sunshine. Photo: Dallas Glass

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Moderate east winds on Tuesday built small wind slabs on the lee sides of ridges. In locations that received less snow (Crystal/White Pass) these are more like small wind-loaded pockets. However, on the volcanoes, you could encounter shallow slabs up to a foot thick. Look for signs on wind loading like small sharp cornices, drifts, and textured surfaces to highlight where these slabs may exist. While they should be rather small, don’t let them knock you over and take you somewhere you don’t want to go.

    (3/21/2023) Clear signs of wind loaded slopes can help you anticipate slabs. Photo: Dallas Glass

Avalanche Discussion

Temperatures could be quite chilly first thing in the morning at some trailhead locations in the mountain valleys and passes due to temperature inversions. Don’t worry, with mostly sunny skies, things should warm up quickly. Clouds may increase in the afternoon and you could even see a few flurries. If clouds come in earlier than expected, you may not experience enough daytime warming to create wet avalanche concerns. 

It’s been warm around the West South zone for several days. Above-freezing temperatures have been the norm. Not surprisingly, this resulted in several rounds of natural loose wet slides primarily from steep rocky slopes receiving sunshine. This warm weather, sunshine, and a bit of rain affected the surface in all areas expert higher elevations shaded terrain. In these locations softer drier snow still exist. Expect icy slopes, breakable curst, frozen debris, and punchy snow at lower elevations (below about 5500ft) and on E-S-W aspects near and above treeline. 

With this prolonged warm-up other “shed” style avalanches remain on our minds. Cornice collapses, glide failures, and avalanches breaking into older layers could happen in very isolated areas. Pay attention to the terrain above you and don’t hang out in areas underneath crevasse-like cracks, looming cornices, or large complex terrain basking in the sun.

Regions covered