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 8 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Human-triggered avalanches will be possible today due to wind slab and storm slab avalanche problems. MODERATE avalanche danger exists at all elevations. Maintain awareness of the conditions and terrain while traveling in the backcountry and use this information to create safety margins that avoid the avalanche problems. 

Problemi valanghivi

  • Wind Slabs

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

    New snow and strong southwest winds during the night will have created new wind slabs on wind-loaded N-NE-E aspects and on some cross-loaded NW and SE aspects in near and above teeline terrain. These new wind slabs will continue to grow today as more snow and wind impact the forecast area. In some places, these slabs may rest on top of the weak surface snow that existed before the storm. Human-triggered wind slabs will be possible today and some of them could involve enough snow to bury or injure a person. Some of these wind slabs could be remotely triggered or propagate across a larger area than expected. 

    Maintain awareness of the conditions and terrain by looking for signs of wind-loading like cornices above a slope, blowing snow, or wind created textures on the snow surface. Avoiding these wind-loaded areas where fragile wind slabs may exist and planning to recreate in lower angle more sheltered terrain will help avoid this potential avalanche problem and find fun soft snow. 

  • Loose Dry

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

    Human-triggered storm slab avalanches may be possible today especially where the new snow sits on top of the weak surface snow that existed on most northerly aspects. If storm slab avalanches do occur, they should remain relatively small due to the amount of new snow accumulation. Small avalanches can still have large consequences especially when terrain traps like cliffs, gullies, trees, lakes, etc are involved. They could also help push a person into any of the numerous early season obstacles. 

    Look for clues like recent avalanche activity, shooting cracks, or feeling a softer layer of old snow under the new snow to help figure out where storm slabs may exist. Use this information to avoid those potentially problematic areas. When in doubt, assume the slope may be unstable and move to lower angle terrain where avalanches are unlikely and fun recreation conditions still exist.

Avalanche Discussion

* Yesterday observations from Powderhouse Peak (Luther Pass), Tamarack Peak (Mt. Rose backcountry), and Castle Peak (Donner Summit) found weak unconsolidated snow on the surface on northerly aspects. This data is consistent with other observations from around the region this week showing widespread near surface facets on northerly aspects.

* A mix of scoured surfaces, wind packed snow, and crusts existed on the more exposed slopes before this storm.

* On less exposed southerly aspects, variable crusts existed on many of the slopes prior to the storm.

* Early season conditions still exist with lots of obstacles on or near the snow surface in many places.

Regioni coperte