Lawinenlagebericht

West Slopes South

Northwest Avalanche Center
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Lawinengefahr

Wed
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
2 · Mässig
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Veraltet — dieser Lagebericht ist last year abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Don’t let the abundant sunshine cloud your judgment on Tuesday. Large, deadly, and unpredictable wet avalanches remain a possibility. There isn’t a way to confidently manage this problem, so avoid being on or under any steep open slopes.   

Lawinenprobleme

  • Wet Slabs

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

    Wet avalanches should be shaping your travel plans on Tuesday. While the sun won't help matters, the danger will exist all day on all slopes, regardless of whether the slope is sunlit. Avalanche frequency may be on the decline, but the size of a slide could hold steady, or even increase. 1-2.25" of rainfall from the storm will continue to migrate through the snowpack, testing its strength and stability as it percolates and pools. The full menu of wet avalanche problems—wet slabs, wet loose, and glide—all remain on the table. It is nearly impossible to predict when a given slope will reach peak instability for a deeper wet slab or glide avalanche. Often, large and deadly slides can occur days after rainfall ends. No refreeze and soaring temperatures will only add more fuel to the fire. Cornices could also fail in the heat and trigger a dangerous slide below.

    Even if you don't observe signs of previous large avalanche activity, a destructive slide could release on its own and without warning. Large avalanches are mostly likely to originate in the upper and middle-elevations, though they could easily descend thousands of feet down into the lower elevations. Be aware of what is above you, even if you can't see clearly into higher terrain, and don't linger in runouts. Even wet loose avalanches that start out small could gouge deeply into the snowpack and grow plenty large enough to bury a human.

    Due to the combination of consequence and unpredictability, the avalanche conditions on Tuesday won't be "manageable". The safest bet is avoidance. 

    (3/6/2025)

    This very large wet avalanche likely ran during the atmospheric river at the end of February. These types of avalanches can leave deep and heavy debris piles and run into low-angle terrain in the valley bottom.

    Photo: Dallas Glass

Avalanche Discussion

Rain has reached the top of our forecast elevations throughout the zone. Crystal, White Pass, and Paradise have all seen between 10-14" of snow settlement over the past day, indicating that nowhere in the West South escaped the impact of this storm. Our friends at the USGS detected multiple very large to historic avalanches on Mount Rainier and Mount St. Helens, including a D4 that lasted for 20 minutes late at night on the 23rd, while Crystal Pro Patrol noted a gouging wet loose avalanche late in the day Monday. We suspect to see evidence of fairly widespread activity once visibility improves, and we think more slides may yet come down.

Water takes time to percolate through the snowpack and there are many interfaces above the late February AR Crust where it could pool, destabilize the snow, and trigger an avalanche. Patrollers at Crystal and White Pass noted that some interfaces above the old AR Crust are only just starting to see moisture while the wetting front remains relatively high in the snowpack. The take-home is that the cycle likely hasn't yet run its course on every slope. What does this mean for mountain travel? Until we get either proper refreezing or see clear evidence that water has drained past any pre-existing interfaces, there simply isn't any reason to confidently travel in or below avalanche terrain. 

Fortunately, the decision for tomorrow should be pretty simple. Avalanche conditions notwithstanding, you will find arduous, mushy travel conditions in the mountains. It could be a gorgeous day to bike, hike, sunbathe, or do just about any other recreational activity off the snow on Tuesday. 

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