Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

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

Rising freezing levels and sunshine could help the snow to fall from trees, rocks, or cliffs to trigger avalanches as the day goes on. If you are standing in the sunshine and the snow surface is wet and sticky, take note of what could fall on you from above and think about heading toward shaded slopes.

Avalanche problems

  • Loose Wet

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

    On Friday, take a look at the snow surface where you are traveling to determine if the sun’s influence has made it warm and sticky. If so, the snow surface could destabilize and produce some natural Wet Loose avalanches or you may be able to push snow downhill, creating a Wet Loose. These avalanches will be more likely on slopes that see direct sunshine, particularly later in the day as snow surfaces soften, and could be larger as you ascend in elevation. These slides often start at a point and can entrain snow, fan-out, and even trigger slabs as they descend downhill. Besides taking note of the snow surface, you can look for precursors to Wet Loose avalanches such as pinwheels and rollerballs as an indication to head toward shaded slopes to avoid this hazard.

    (3/11/2021) Rollerballs, pinwheels, and small Wet Loose avalanches were observed on Thursday (3/11) at Mount Rainier National Park as sunshine and rising freezing levels destabilized the snow surface.

Avalanche Discussion

Expect continued sunny weather and freezing levels creeping higher on Friday as they approach 6000 feet. This warm-up has been with us for a few days now and on Thursday, small Wet Loose avalanches and rollerballs were observed throughout the West South. These avalanches have needed some time to overcome the cool morning temperatures, meaning that hazard is typically increasing throughout the day as the sun’s influence grows stronger. We expect this same pattern to continue into the start of the weekend. In addition to Wet Loose avalanches, continue to give other avalanche hazards associated with a warm-up such as cornice, glide, and icefall a wide berth as we transition toward a more spring-like snowpack. On aspects that do not see direct sunshine, you could find that cold dry snow still exists over the 3/5 crust. Signs point to this snow’s bond to the crust weakening, so keep dry loose avalanches or pockets of wind-drifted snow on your radar on these slopes and don’t get swept off your feet in consequential terrain.

We have decided to remove the Deep Persistent Slab problem from our official problem list in the West South. Although the weak snowpack structure remains, a few data points have made us feel more comfortable with this layer than we have recently.

  1. Our last confirmed natural avalanche on the Mid-January crust/facet layer in the West South was over a week ago. (Weekend of 2/27-2/28 near Crystal Mountain).
  2. We have a generally strong and well-settled upper snowpack above this layer. This includes the most recent 3/5 crust, which is thick and supportable in most locations throughout the zone.
  3. Since our last major loading event on this layer, test results have become more inconsistent than they were previously. 

The Mid-January crust still remains 6-10+ feet deep in the snowpack throughout much of the zone, and we believe it is currently dormant. It may wake back up at some point this season, however. At that point, we will put it back on the official problem list and continue to talk about the dangers this layer presents. Until that time, don’t forget about this layer. If you choose to enter more complex or large avalanche terrain, you should continue to talk with your partners about the low-likelihood/high consequence avalanches this layer is capable of producing. Keep in mind that when they occur, these avalanches have broken trees and descended far distances toward their maximum runouts in valley bottoms. The best way to mitigate your risk is to limit your time in and below large avalanche start zones, paths, and runouts. 

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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