Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
3 · Considerable
Treeline
3 · Considerable
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Out of date — this forecast expired 5 years ago.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

Rain at upper elevations will create dangerous avalanche conditions on Wednesday. You should be leery of any slope over 35 degrees where wet snow exists. Choose safe travel routes far away from overhead hazards and consider avoiding large avalanche paths for the next few days.

Avalanche problems

  • Wet Slabs

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

    Freezing levels are predicted to rise to 9000 feet on Wednesday, meaning rain will reach the summit of the mountains near the crest and most of the frequently visited terrain of the volcanoes. We expect widespread wet avalanche activity to occur throughout the zone overnight on Tuesday into Wednesday as these upper elevations see rain for the first time this season. This could materialize as Wet Slabs, Wet Loose, or even Glide avalanches. We have lumped them all together here into Wet Slab because these problems are often intermingled and difficult to differentiate. To further complicate the matter, precisely predicting wet avalanches is notoriously difficult since they are not well understood. Luckily, you can minimize your exposure to these erratic avalanches by choosing safe travel routes, staying off slopes over 35 degrees, and being aware of the terrain above you at all times.

    Lower elevations have received several rounds of rain and freezing rain since January 6th, possibly making them better suited to handle continued liquid precipitation. That doesn’t mean that hazard does not exist. Wet avalanches can occur hours or even days after water is introduced to the snowpack.

    (1/11/2022)

    Wet avalanche activity was observed in Silver Basin near Crystal Mountain as temperatures rose and rain fell on dry snow on Tuesday (1/11). Expect more widespread wet avalanche activity in the coming days.

    Photo: Mike Ward

Avalanche Discussion

The slow warmup that has been affecting the West South zone will continue overnight Tuesday as temperatures slowly climb toward 9000 feet on Wednesday. Precipitation is expected to be the heaviest overnight and into the morning hours before tapering by Wednesday afternoon. You could find the highest danger first thing in the morning but should remain cautious even as the day wears on and precipitation subsides. Lingering wet issues will continue throughout the forecast period as the snowpack adjusts to its new load. This includes additional wet avalanches, cornice collapses that could act as a trigger on the slopes below, or blocks of snow and ice shedding from trees and rocks.

Recently, very large avalanches have been reported within the zone, some occurring during the previous storm cycle and some in the days that followed. Uncertainty surrounding these events has us on edge during this warm-up. Slopes that did not produce very large avalanches in the last cycle may reach their tipping point due to high freezing levels, rain, a falling cornice, or a wet avalanche during this cycle. Consider avoiding open alpine slopes and large avalanche paths until this storm has played out and the snowpack has had time to adjust to this significant load.

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