Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Tue
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
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In sintesi

With continued rain and warm temperatures, avoid traveling on steep slopes where wet avalanches are likely. Wet avalanches can be unpredictable and may travel long distances through elevation bands. If you choose to head into the mountains, know what terrain is overhead, and don't linger in gullies or runouts from large, steep slopes at higher elevations.

Problemi valanghivi

  • Wet Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    2–3

    Avoid steep slopes where you are sinking deeply into saturated snow and could trigger a wet avalanche. If you're above 6000ft and rain is falling on dry snow, wet loose avalanches will be more likely and more widespread. Natural wet slabs are unpredictable, so if you're traveling in the mountains, make sure you are aware of any overhead hazard from the terrain above you. Travel quickly through runouts and gullies where large avalanches can channelize and run long distances into lower elevations. Cornice failure and glide avalanches involving the entire season's snowpack should also be on your radar. Avoid traveling below deep, open glide cracks and overhung cornices. 

    Wet loose and wet slab avalanches will still be fairly widespread on Monday. While an initial round of avalanches occurred with rain and warming on Sunday, upper elevations likely did not see much rain. But as temperatures continue to warm and water percolates farther through the snowpack, much larger and unpredictable wet slab avalanches can occur. 

    (3/18/2024)

    An example of a wet slab avalanche from a previous season in Wenatchee Bowl.

    Photo: Josh Hirshberg

Avalanche Discussion

We are headed into day two of an atmospheric river, and temperatures will continue to warm. By Monday evening, freezing levels will reach the upper extent of our forecast area. Strong winds and precipitation will be most intense overnight and into the early hours of Monday but will be slow to let up throughout the day. The highest elevations may not transition to rain until later in the day, so if you manage to make your way up above 6500ft, expect to find large and dangerous wind slabs on steep, exposed terrain. Travel will be arduous in deep, wet snow at most elevations on Monday. 

Stevens Pass Ski Patrol reported widespread wet loose avalanches on Sunday. Most were wet loose avalanches within the most recent storm snow, but one isolated slide gouged into deeper layers of the snowpack.

Before this atmospheric river, observers reported numerous triggered avalanches in the past few days, with many occurring on leeward, wind-loaded slopes. There were reports of human-triggered and natural avalanches big enough to injure or kill a person (D1.5-2) on Friday. Saturday was a similar story. Steven's Pass DOT triggered large avalanches during morning control work. Steven's Pass Ski Patrol found reactive, small wind slab avalanches during avalanche control work. A skier was caught and carried in an avalanche in Highland Bowl, in the backcountry just outside the Stevens Pass Ski Area. Thankfully, the individual was uninjured. All these slides indicate that the snowpack was dry and layered before the rain. As water moves deeper into the snowpack, these previously dry, weak interfaces can lead to very large wet slab avalanches. 

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