Bollettino valanghe

Central Sierra Nevada

Sierra Avalanche Center
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Pericolo valanghe

Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 7 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

LOW avalanche danger will exist at all elevations this morning while the snowpack remains frozen. As the overnight refreeze melts, the danger will increase to MODERATE at all elevations due to the possibility of loose wet avalanche problems. 

Problemi valanghivi

  • Loose Wet

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

    Loose wet avalanches will become possible once daytime warming melts through last night's refreeze. Some of them could be small. Some could be large enough to have more serious consequences, especially on long, steep, sun-exposed slopes. Areas with terrain traps could magnify the severity of this problem. Wet surface snow, pinwheels, and roller balls can foreshadow larger loose wet avalanches.

    A frozen snow surface can give way to shallow wet snow on a supportable crust (corn) to deep, unsupportable, sloppy, wet snow in a short amount of time. In many areas, the snow may skip over the corn state today because it has not been through enough melt-freeze cycles. Watch for these changes and time backcountry travel to be off sun-exposed slopes before the deep wet snow forms. Exploring more northerly aspects to find areas where softer cold snow still lingers could also reduce exposure to loose wet avalanche concerns.

Avalanche Discussion

* Observations from Hidden Peak and Sunrise Bowl yesterday found wind affected snow surfaces in exposed near and above treeline areas. A firm wind slab on top of a softer layer of snow existed on multiple aspects in both places. Tests targetting the wind slabs on NE and SW wind-loaded test slopes on Hidden Peak did not show signs of lingering instability.

* Sheltered northerly aspects above 7500 ft. on Hidden Peak still held cold ankle deep soft snow.

* Wet snow had started to form on sun-exposed E-SE aspects on Hidden Peak by mid-morning. Ski cuts could trigger roller balls and pinwheels by noon. The snow on these aspects had not transistioned to corn yet and was wet and sticky.

Regioni coperte