Lawinenlagebericht

West Slopes South

Northwest Avalanche Center
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Lawinengefahr

Thu
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
2 · Mässig
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Kernpunkte

Due to recent heavy rain and continued balmy temperatures, large wet avalanches and cornice failures remain a serious concern. You won't be able to confidently assess for wet slab or glide avalanches, so consider giving a wide margin to steep slopes and move quickly if crossing below an avalanche path. With the threat of afternoon thunderstorms, make sure you have a plan to exit the mountains quickly if need be.

Lawinenprobleme

  • Wet Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    2–3

    Wet slab, glide, wet loose, and cornice failures could all occur on Wednesday. Though the likelihood of larger releases may be on the decline, the consequences haven't changed at all. Large and destructive avalanches could fail on their own and without warning. These slides are most likely to originate at the upper and middle-elevations. Wet loose avalanches and jumbo rollerballs could fail naturally or be triggered by a human, and even those that start out small could gouge deeply into the snowpack and grow large enough to bury a backcountry traveler. Cornices are sagging in the heat and if they fail, they could trigger slab or loose avalanches below. Put it all together and you have overlapping types and sizes of avalanches to contend with.

    The thing of it is, predicting when a wet slab will release on a specific slope is nearly impossible. We wouldn't be surprised if you don't see large avalanches on steep slopes tomorrow. But we also wouldn't be surprised to see a very large avalanche that breaks trees and runs thousands of feet into the valley bottoms. How to manage uncertainty like that is a personal decision, but recognize that this problem is still out there and if you are in the wrong place at the wrong time, it would likely be unsurvivable. Consider either avoiding steep slopes and their runouts altogether (the safest choice) or strictly limiting your time on and below avalanche paths.

    (3/25/2025)

    A very large wet slab avalanche from both sides of the Nisqually Glacier. This beast likely occurred on 3/24.

    WS-N-R4-D3-O

    Photo: NPS Rangers

Avalanche Discussion

Well, that was a hot one! Under sunny skies and light winds, temperatures at the top of Crystal Mountain soared to 51 degrees F, while Paradise reached 60! Even Muir hit 32 at 10,000ft. Large to very large, and even historic wet slab avalanches were observed in the Goat Rocks, on Mount Rainier, and near Crystal Mountain. Best we can tell, these slides occurred during, or immediately after the 1-2.25" of rainfall on 3/23-3/24. The width and depth of these avalanches is impressive and highlights the deep and layered snowpack we had in place going into the storm. Continued wet loose activity was observed by Crystal Pro Patrol and NWAC forecasters near White Pass on Tuesday, who cataloged some of the recent slides, noted sticky travel conditions, and were able to trigger rollerballs larger than a human!

Though that may have been the crescendo for large avalanches, free water in the snowpack is still percolating to parts unknown, and we don't trust it. While the lower-elevation snowpack appears unlikely to produce a large avalanche, interfaces above the late February AR Crust may only just be seeing their first bits of moisture. It's plausible that the previously observed avalanche activity indicates that those interfaces already saw sufficient water to fail and avalanche if they were going to. Or it may simply suggest that differences in snowpack structure, slope character, and ultimately how water flows through snow have led to avalanches on some slopes, while others may still be waiting for their moment to release. Without a good way to answer that question, what we need is a good refreeze to put this problem to bed. That will happen eventually, but eventually isn't Wednesday. 

What does this mean for mountain travel? Well, for one, travel conditions are sloppy, sticky, and arduous, at all elevations. As far as the avalanches are concerned, we can't rule out a large and destructive slide, and that should be the thing shaping your decision-making. The general weather pattern for the next few weeks looks decent and there is plenty of snow in the mountains. The transition season can be tough, but stay patient; both avalanche and travel conditions should improve soon. 

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