Bollettino valanghe

Central Sierra Nevada

Sierra Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
Open full map
Non aggiornato — questo bollettino è scaduto 12 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

MODERATE danger exists on slopes 35 degrees and steeper on wind loaded W-NW-N-NE-E-SE aspects in near and above treeline terrain. Some pockets of CONSIDERABLE danger may still lurk on those same aspects and elevations south of Hwy. 50 where more snow fell. Pockets of MODERATE avalanche danger may also remain on some slopes 35 degrees and steeper on NW-N-NE-E aspects in near and below terrain. Human triggered wind slab and storm slab avalanches remain possible today.

Problemi valanghivi

  • Wind Slabs

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

    Human triggered wind slab avalanches will remain possible today. The largest and most fragile wind slabs will exist on leeward slopes in near and above treeline terrain south of Hwy. 50 where much more snow fell. In some of these areas human triggered wind slabs may remain likely. The most recent wind slabs have formed on top of a mix of older wind slabs and lighter snow layers. Underneath these layers old crusts, layers of weak sugary snow, and layers of lighter storm snow still remain. Most of the wind slabs that fail today should do so at or above the interface between Wednesday night's snow and yesterday's snow (1-3 ft from the surface). However, some of them could step down the the old snow layers below Wednesday night's snow making them much deeper. Due to the shifting south and southwest winds the wind slabs could exist on W-NW-N-NE-E-SE aspects in near and above treeline terrain.

  • Loose Dry

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

    Some fragile storm slabs could still lurk on the below treeline NW-N-NE-E aspects where thin layers of soft sugary snow exist below the new snow that has fallen since Wednesday night and where shallower storm snow weaknesses may remain within the recent snow. Human triggered storm slab avalanches may remain possible in these areas. These slabs could measure 1 to 2+ ft. in depth. The deepest and most fragile of these storm slabs will likely exist on sheltered N aspects above 8000 ft. As with the wind slabs areas south of Hwy. 50 will be the most suspect due to the fact that they received much more snow.

Avalanche Discussion

Yesterday observations along the Becker Peak/Talking Mtn. ridgeline revealed new, fragile wind slabs on wind loaded N-NE aspects in near and and above treeline terrain. By mid day some of these wind slabs had reached 16 inches in depth even though only 3-4 inches of snow had fallen. Stomping on ridgelines near these wind slabs or dropping small oven sized cornice pieces on the wind loaded slopes triggered small wind slab avalanches in this area. In addition to these intentionally human-triggered slides one small natural wind slab avalanche occurred in this area yesterday. All of these slabs measured between 6 and 16 inches in depth and failed at the interface between the snow that fell yesterday and the snow that fell on Wed. night.

Below 7600 ft. near Echo Lake, heavy wet snow existed and ski cuts could trigger minor roller balls on N-NE aspects. In this area and farther north on Andesite Ridge a period of sunshine in the morning and warming temperatures did cause the surface snow on sun exposed aspects up to 8200 ft. to also become wet and heavy during the morning yesterday.

Regioni coperte