Bollettino valanghe

East Slopes South

Northwest Avalanche Center
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Pericolo valanghe

Mon
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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In sintesi

It might be a sloppy day out in the East South with warming temperatures and the potential for wet avalanches or small slabs in the recent snow. While less likely but more consequential, these avalanches could step down to deeper layers and break widely across terrain. Rollerballs, cracking, or recent avalanches are signs to choose lower angle terrain. 

Problemi valanghivi

  • Loose Wet

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

    Warming temperatures and rain on the recent snow could produce small wet loose avalanches in steep terrain. Wet avalanches often start from trees or rocks shedding snow onto slopes below, but you can also trigger them with your skis or snowmobile. If it's raining on dry snow, or snow becomes wet and heavy, consider moving to lower angle slopes. There is potential for these small wet avalanches to step down to deeper weak layers, triggering a larger slab avalanche 2-4ft deep. Consider these consequences before riding on steep terrain with wet, heavy snow. 

    (12/14/2023)

    Wet loose avalanches often release from steep rocks and cliffs overhead.

    Photo: Katie Warren

  • Persistent Slabs

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

    We are uncertain about the extent of the persistent slab problem in East South. However, previous avalanche activity in this zone on persistent weak layers, very large avalanches as recently as Friday in West South, and avalanches to the north (East Central) make it a good bet this tricky problem also exists here. With a few inches of new snow or rain, small storm slabs or wet avalanches could step down to these layers, producing a very large avalanche.Weak facets exist on and within several crust layers buried deep in the snowpack. These avalanches could now be 2-4ft deep and potentially unsurvivable. These persistent problems take prolonged patience. Use conservative travel techniques and give yourself wide safety margins around large open terrain. Avoid steep slopes where a smaller avalanche could step down to these deeper weak layers. 

    (1/11/2024)

    Explosive triggered persistent slab avalanches at nearby Crystal Mountain. These widely propagating avalanches could also occur in the East South zone. 

    Photo: Crystal Mountain Pro Patrol

Avalanche Discussion

A few inches of snow overnight will likely fall on freezing rain and melt-freeze crusts formed from rain and warm temperatures on Friday and Saturday. You could find a variable bond with this old snow surface, so make frequent observations as you travel. Use Kickturn tests, small test slopes, or hand pits to observe the bond to the old snow surface. If these produce cracking or fail easily, avalanches are more likely.  

There is also a chance for freezing rain on Sunday, so don't be surprised to find your goggles icing up. 

Warming temperatures and rain on snow are something the east slopes of the Cascades haven't experienced for a while, and the snowpack is undergoing a big transition. As we step out into the mountains after these shifts, be prepared to make assessments as you travel, and don't be surprised to see strange or quickly changing conditions. Build wider margins into your travel plans to account for this, and pay attention to warning signs such as collapsing, shooting cracks, or recent avalanches. We haven't had much recent info from East South since last weekend. But on Thursday in East Central, widespread sensitive storm slabs failed on the 1/16 interface of weak faceted snow. White Pass Ski Patrol reported a few natural avalanches failing on the recent 1/16 interface on Friday. An NWAC forecaster at Crystal Mountain saw a suspiciously large avalanche in Morse Creek, very close to the border of East South. With big avalanches and a lot of uncertainty, it's always a good default to more conservative terrain.

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