Bollettino valanghe

Central Sierra Nevada

Sierra Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
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

Early this morning, avalanche danger is LOW for all elevations and aspects. Avalanche danger will quickly increase to MODERATE danger by the late morning hours for all elevations and aspects in response to daytime warming. Small human triggered loose wet avalanches are expected today. Small naturally occurring loose wet avalanches are possible in isolated areas.

Problemi valanghivi

  • Loose Wet

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

    Last night, overnight minimum air temperatures were well above freezing and skies were clear. Snow surface refreeze is expected to be fairly superficial again this morning, having been dependent entirely on radiational cooling. A few hours of supportable snow surface conditions are expected early this morning. By late morning, daytime warming is expected to have caused sufficient snow surface melting to allow for loose wet snow avalanches to occur. Small human triggered loose wet avalanches are expected today with small natural loose wet avalanche activity becoming possible by the afternoon hours.

Avalanche Discussion

Observations made yesterday on Becker Ridge (Echo Summit area) revealed that the previous night's snow surface refreeze during above freezing air temperatures had been very superficial and dependent entirely on radiational cooling under clear skies. Southerly aspects held 4 inches of melt-freeze crust on top of 10 inches of residual wet snow from previous days melting. On N aspects steeper than about 38 degrees at 8,000', a half inch thick breakable melt-freeze crust remained on the snow surface at mid day. On most sun exposed N aspects, 4 inches of wet surface snow sat on top of stable recent storm snow, unaffected by melt-freeze. Small loose wet avalanches, roller balls, and pinwheels failing at the interface between wet and dry snow were very easily human triggered in most areas. Several small natural loose wet avalanches were observed from Hwy 89 on NE-E aspects between 7,000' and 9,000' on Flagpole Peak (Echo Summit area) and Mt. Tallac (Desolation Wilderness area).

Regioni coperte