Bollettino valanghe

Central Sierra Nevada

Sierra Avalanche Center
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Pericolo valanghe

Alta quota
1 · Debole
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 11 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

LOW avalanche danger continues for all elevations and aspects. Human triggered loose wet avalanches may occur this afternoon in isolated areas on E-SE-S-SW aspects on slopes 37 degrees and steeper. Normal caution is advised.

Problemi valanghivi

  • Loose Wet

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

    A decent snow surface refreeze is expected to have occurred again last night due to a combination of below freezing air temperatures in some locations and radiational cooling in other areas where air temperatures were above freezing. More upper elevation locations are reporting below freezing air temperatures this morning than has been the recent trend. Many of the mid elevation locations were still in the upper 30s overnight with radiational cooling allowing the snow surface to refreeze. Last night's refreeze is likely to be similar to what was observed yesterday morning.

    Supportable conditions are expected through the morning hours today. Sometime during the mid day to afternoon hours conditions will become less supportable and loose wet snowpack instability will increase. Human triggered loose wet avalanche activity could occur this afternoon in isolated areas on E-SE-S-SW aspects. Some amount of cloud cover, slightly cooler air temperatures, and NE winds will help to keep the snow surface from melting too rapidly today.

    Once several inches of wet snow form on the snow surface and body weight boot penetration approaches 1 foot deep or more into surface wet snow, it is time to take active measures to avoid avalanches. Change to a more northerly or westerly aspect and/or move to slopes less than 35 degrees in slope angle without steeper terrain above. Planned timing of travel in avalanche terrain is critical for the preferred mix of frozen to melting, but still supportable snow surface conditions.

Avalanche Discussion

Across the forecast area, the snowpack on E-SE-S-SW aspects has for the most part adjusted to the post storm warming over the past 11 days. Widespread melt-freeze conditions are well established on E-SE-S-SW aspects. Areas of dry snow, unaffected by melt freeze linger on northerly aspects above 8,000'. Surface crusts exist on northerly aspects below 8,000'. Observations made yesterday on the north side of Carson Pass and received yesterday from the south side of Jakes Peak indicated that a strong snow surface refreeze had occurred in both areas the night before. The top 6 to 8 inches of the snowpack had formed a thick dense melt freeze crust on E-SE-S-SW aspects. Between 8,000' and 9,500' snow surface melt was noted to occur fairly gradually during the mid morning hours, with conditions remaining supportable during the late morning hours.

Regioni coperte