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

In sintesi

MODERATE avalanche danger continues for all elevations and aspects on slopes 35 degrees and steeper. Wind slabs are building in near treeline and above treeline areas on NW-N-NE-E-SE aspects. Rain on snow is keeping the possibility of loose wet avalanche activity ongoing. Increasing avalanche danger will occur this evening through the overnight hours with CONSIDERABLE avalanche danger expected and HIGH avalanche danger possible. The likelihood of natural and human triggered slab avalanches will steadily increase today and tonight.

Problemi valanghivi

  • Wind Slabs

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

    Snow levels are expected to lower today and snowfall intensity is forecast to increase late this afternoon or this evening. This combined with ongoing gale force SW winds will allow wind slabs to continue to build in size and become increasingly widespread near treeline and above treeline on NW-N-NE-E-SE aspects. Existing small wind slabs above 8,000' this morning will become larger as the day progresses. As snow level falls this morning, wind slabs will become more widespread in the 7,000' to 8,000' range. A rapid building of wind slabs is expected this evening during the forecast period of high intensity snowfall.

    Areas of potentially unstable wind slabs can be identified and avoided. Look for signs of recent avalanche activity, blowing snow, wind pillows, cornices, and human triggered snow surface cracking. Avoid slopes steeper than 35 degrees where signs of wind slabs are present.

  • Loose Wet

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

    Rain on snow has created wet surface snow on all aspects below 8,000' to 8,500'. Deep wet snow penetration of skis and snowmobiles is expected to remain ongoing today. Human triggered loose wet avalanche activity will remain possible even as snow level lowers today. Wet snow in the upper portion of the snowpack will take some time to refreeze, remaining loose and wet even after rain changes to snow and air temperatures cool.

    Measure penetration into wet snow by stepping off of equipment from time to time today. In areas where body weight penetrates a boot into wet snow up to boot top height or deeper, avoid slopes steeper then 35 degrees and stay out from under steeper slopes above.

Avalanche Discussion

Observations made yesterday morning on Rubicon Peak (West Shore Tahoe area) and received from yesterday afternoon on Castle Peak (Donner Summit area) revealed a poor to nonexistent overnight snow surface refreeze and deep wet snow. The presence of deep wet snow was directly linked to elevation and changed little by aspect below 8,000'. In the morning hours, conditions remained skier supportable above 8,000' on Rubicon Peak. By the afternoon hours, deep wet snow with ski penetration on 4 to 6 inches was reported from Castle Peak above 8,000'.

Regioni coperte