Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Continued warm weather will be opposed by increasing winds and clouds on Sunday to influence the snowpack This could play out a little differently depending on your location in the zone, but you’re most likely to encounter avalanches on steep slopes where the surface is wet and sticky. Consider the threat of larger and more destructive avalanches due to cornice falls or other shedding events when making your travel plans.

Avalanche problems

  • Loose Wet

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

    Our warm spell should continue Saturday night into Sunday despite some incoming clouds. This will keep Wet Loose avalanches as the most likely problem you’ll encounter during your travels. It could be a bit tricky with warmer morning air temperatures than Saturday forecasted, but a return of cool easterly winds. These competing weather factors have us thinking that avalanche activity will be more muted than what we experienced on Saturday. Take note if the snow surface is wet and sticky or if you see new rollerballs and pinwheels wherever you’re traveling. Wet Loose avalanches could soon follow, starting at a point and fanning out as they descend. To manage this problem, you should head to shadier slopes, keeping aware of overhead hazards such as cornices or hanging blocks of snow that could release without warning.

    (3/18/2023)

    Wet Loose avalanche on a steep sunny slope. Not how it originated at a point, near trees and rocks.

    Photo: Dallas Glass

Avalanche Discussion

Most NWAC weather stations around the zone recorded temperatures well into the 40s on Saturday, with a few lower-elevation stations soaring into the 50s! Observations indicate that there were plenty of Wet Loose avalanches up to size D2 as a result of these warm temperatures. While winds were a little stronger near the crest than originally anticipated, the springtime weather finally won out later in the day as slopes reached their tipping point. Reports from White Pass and Mount Rainier relayed that shaded slopes appeared to hold onto mostly dry snow, but trees were shedding and dripping even on the northerly half of the dial. 

As alluded to above, a poor overnight freeze is expected Saturday night, so we could pick up right where we left off on Sunday morning with wet and sticky surfaces. In contrast to Saturday, we aren’t expecting full sunshine plus we should see a return of breezy easterly winds, particularly near the crest where they could even approach strong. This has us dropping the hazard level a notch, but conditions remain largely the same. In general, the snowpack does not like rapid change. Coming out of a recent cold and snowy pattern right into this warm period is considered rapid on a snowpack scale and we could see some unique avalanches as a result. The threat of isolated very large avalanches where blocks of snow such as cornices or glides fail due to the springtime temperatures is still on our radar.

Although the winds will likely be strong enough to drift snow into Wind Slabs on Sunday, there likely isn’t much snow available for transport. On more northerly aspects where the sun’s influence hasn’t been as strong, you could still find well-settled powder and some of the more pronounced cornices. If you’re going to encounter a newly formed or lingering hard Wind Slab, it's in those locations. As a weak storm system moves into the zone in the afternoon, you might even see a dusting of snow up high or raindrops down low. If you encounter rain falling on dry snow, anticipate Loose Wet avalanche distribution to expand to northerly aspects.

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