Bollettino valanghe

Central Sierra Nevada

Sierra Avalanche Center
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Pericolo valanghe

Fri
Alta quota
1 · Debole
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 5 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

While daytime warming may create some small loose wet instabilities in below and near treeline areas, larger wet snow instabilities should remain unlikely due to a strong refreeze, continued wind, and previous melt-freeze transitions. The avalanche danger will remain LOW at all elevations. Icy surfaces and variable snow conditions could present additional hazards today including long sliding falls. Travel using normal caution and be willing to step back into safer terrain if conditions warrant.

Problemi valanghivi

  • Loose Wet

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

    Continued NE winds, a strong refreeze, and several previous melt-freeze transitions should work to limit wet snow instabilities today despite the sunny weather and warmer temperatures. Enough warming should occur for some shallow, soft, wet snow to form on sun-exposed slopes. Small roller balls and pinwheels may occur in some places especially near things that heat up faster like rocks or trees but larger loose wet avalanches are unlikely today. In many other areas, variable snow conditions will exist including firm icy surfaces, uneven wind scoured surfaces, and pockets of "dust on crust" or soft cold snow.  

    Using timing and terrain can help find decent conditions today. Giving the sun a chance to soften the firm surfaces into corn conditions represents one strategy for finding softer snow. Seeking out sheltered N facing slopes where cold snow may linger represents another. Monitoring the snow conditions and talking about them with your group can help avoid ending up in an area where conditions exceed your group's abilities or comfort levels. 

Avalanche Discussion

* Gale force NE winds continued scouring wind-exposed areas yesterday. NE wind scouring has extended down to open below treeline areas.  Observers did report limited blowing snow yesterday along the Sierra Crest, but the winds had already scoured most of the snow away, so very little snow remained for transport.

* Recent wind scouring has exposed icy rain crusts and created firm snow surfaces in near and above treeline areas.  Travel concerns including the potential for long sliding falls could exist in these areas.

* Pockets of shallow, cold, unconsolidated snow still exist on some shaded, below treeline, N-facing, wind-protected slopes steep enough to avoid any direct sun. Along the Sierra Crest, "dust on crust" conditions exist since this shallow soft snow exists on top of a firm rain crust. In the Mt. Rose area where the rain crust does not exist, this soft snow rests on top of more dense snow. 

* A melt-freeze crust has formed on any slopes that have received sun including low angle N aspects. On the southerly aspects, soft wet snow has been forming by mid-morning. On the other aspects, the crusts range from firm and supportable to thin and breakable.

Regioni coperte