Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

Tue
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Monday should be the warmest day of the past week. Even though the rain should stop, that doesn’t mean huge wet avalanches can’t occur. Give the mountains time to adjust by limiting your exposure to avalanche terrain. 

Avalanche problems

  • Wet Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3

    Wet avalanches could still occur on Monday due to free water in the snowpack and warm temperatures. These types of slides are poorly understood and often intermingled. Snow could shed from rocky ledges, cornices could sag and fail, and humans could push heavy snow on steep slopes. Any of these avalanches are dangerous in their own right. But the more significant concern is that they act as triggers for deeper and more dangerous slabs. We’re talking about low-likelihood, high-consequence slides, so limit the amount of time you spend in avalanche terrain.

    (1/28/2024)

    An explosives-triggered avalanche at Crystal Mountain that propagated widely while exposing rock and dirt.

    [N 6700' WS-AE-R3-D3-O]

    Photo: Crystal Mountain Pro Patrol

Avalanche Discussion

The atmospheric river that soaked the West South zone started to dissipate on Sunday. On average, the zone recorded roughly 3 inches of rain since Friday night. The volcanoes recorded slightly more, and the crest a bit less.

Reports of its damage are slowly trickling in. Crystal Mountain Pro Patrol triggered several very large avalanches with their mitigation efforts on Sunday morning. Some of these slides broke widely and scoured down almost to the ground, exposing dirt and rocks. Multiple large avalanche crowns were observed in the surrounding terrain near Crystal. The patrol also reported witnessing a natural slab avalanche in terrain adjacent to the resort. It occurred mid-morning on Sunday and produced two crowns.

On Saturday, Mount Rainier Nordic Patrol reported a soaked upper snowpack, rain runnels, and small avalanches containing snow and rocks at lower elevations near the access road. The USGS sent along seismic reports of up to nine large to very large avalanches occurring throughout Mount Rainier National Park. They also sent along a very large avalanche reading from the Shoestring Glacier on Mount. St. Helens. 

This has been a unique period within the West South zone. Our previously known weak snowpack structure, mainly focusing around the Solstice Crust, has produced a steady stream of very large avalanches all month. This past week's warm and wet weather has really started to stress the snowpack, culminating in it coming unglued over the weekend during the atmospheric river. On Monday, we are expecting the warmest temperatures of this period. With a snowpack already saturated with water, there is uncertainty about how the day may play out. While the likelihood of triggering may lean toward Moderate danger, the travel advice and size of these potential avalanches align more with Considerable. 

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