Bollettino valanghe

East Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Tue
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

As snow surfaces warm up in the sunshine, loose avalanches should be on your mind. The complex freezing levels make it challenging to anticipate this problem in advance, and avalanches may be more dry loose than wet. Still, use caution on steep, sunny slopes. Wet snow surfaces, rollerballs, or natural loose avalanches are signs to move to lower-angle terrain. 

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    You can trigger loose avalanches on steep slopes, or they can release naturally from snow shedding off trees or rocks. You'll likely find this problem on steep southern slopes warming up in the sunshine. With variable freezing levels, cold east-flow, and inversions, it will be challenging to anticipate where this problem will occur in advance. They may also be more of a dry loose variety than wet loose. It all will depend on how quickly the pool of cold air east of the Cascades is eroded. Use key observations, such as natural loose avalanches, pinwheels, trees shedding snow, or moist surface snow. When or if you start to see these signs, move to lower angle terrain. 

    Cooler temperatures in the lower elevations may make wet avalanches more widespread at mid and upper elevations. 

Avalanche Discussion

Monday will be another day of cold, cloudy valleys, with potential for warming and sunshine at upper elevations. Surface crusts formed on Saturday will have to break down before wet loose avalanche activity increases. In addition,  if the warming holds off or it's cloudy, we might not see much avalanche activity at all. But the signs of loose avalanches typically present themselves early, giving you time to move off steep slopes. Whether you find wet loose or dry loose avalanches, watch for terrain traps that can increase the consequences of small avalanches. 

On Saturday, a professional observer documented the impacts from sunshine and warming, noting numerous loose avalanches in steep, cliffy terrain. As surface snow warmed and became more cohesive, they could also trigger small storm slabs on test slopes. We expect that storm and wind slab instabilities are becoming unreactive. But with limited information, travel with extra safety margins, make frequent observations, and ease into new terrain slowly to account for the uncertainty. 

Regioni coperte