Bollettino valanghe

East Slopes South

Northwest Avalanche Center
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Pericolo valanghe

Wed
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

1 to 2 feet of snow with strong winds recently fell on the Eastern slopes of the Cascades. You can still trigger large avalanches in wind-drifted snow. These avalanches may be easy to trigger on all aspects in alpine terrain, so avoid steep terrain in wind-exposed locations.  

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    The storm favored the eastern Cascades, and the Green Lake SnoTel picked up over 1 inch of SWE and 13 inches of snow. Strong and complex winds shifted directions frequently, building wind slabs on all aspects and sometimes in unusual locations. On Monday, NWAC staff near the border of the East and West South zones easily triggered wind slabs on opposing aspects along a ridge. 

    Snow will continue to trickle in, and wind slabs may be harder to identify with a few inches of fresh snow covering the textured surfaces. But some visual clues such as actively blowing snow, cornices, or drifts around rocks and trees can still help identify wind-affected terrain. You can also use your pole or probe to feel for stiffer snow over softer snow. Finding ridgeline terrain that doesn't have a lingering wind slab at upper elevations will likely be challenging. Therefore, stick to lower-angle routes and avoid start zones if traveling in alpine terrain. Look for signs of instability at lower elevations, such as shooting cracks or collapsing, that indicate you should stick to lower angle slopes or wind-sheltered terrain.

    Rough surfaces and a thin snowpack limit avalanche potential at lower elevations throughout the zone. Still, the snow has been piling up for the last few days, and you may be able to trigger small avalanches in the new snow, even at lower elevations. Use caution in terrain where a small avalanche could push you into rocks, trees, or other obstacles. 

    (4/11/2022) Wind slabs were found in some unusual spots. Fresh slabs were observed on slopes often stripped by the wind. Photo: Dallas Glass

Avalanche Discussion

Expect a mostly cloudy day on Tuesday, with the possibility of a few breaks in the clouds. If you see rollerballs or the snow becomes moist and heavy in the strong April sun, you should consider moving to lower angle or shady slopes. Spring weather in the Cascades is notoriously tricky and can change rapidly. If you are out adventuring during the long days, keep your senses tuned into the snow and look for signs of deteriorating snow stability. Even brief sun breaks can quickly cause wet loose or dry loose avalanche problems. The dynamic spring weather and increased diurnal temperature fluctuations create more uncertainty about what avalanche problems you may encounter during the day. If you observe weather or snowpack conditions you did not anticipate, it may be best to simplify your terrain selection and choose lower angle slopes.Access into areas of the East South with a consistent snowpack has become challenging, and therefore direct observations from the zone are limited. However, snow is piling up on the Early April Crust, and stability test results in nearby White Pass show variable results on this interface. This crust is now 1-4 feet deep, and it is worth digging down to investigate this interface before committing to any steep terrain. With all the new snow, choose conservative terrain and make snowpack observations as you travel. Some southern slopes that were recently snow-free up to 5700ft may now have over a foot of snow. Use extra caution in these lower elevations where obstacles may be lurking just under the new snow, and creek holes may be drifted over or hidden.

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