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
Non aggiornato — questo bollettino è scaduto 6 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

A good overnight refreeze and cooler weather should allow a longer window for supportable snow today, but avalanches of loose wet snow may still be possible this afternoon once the surface crust melts. Cornice fall will also remain possible. By this afternoon MODERATE avalanche danger will exist at all elevations. The last avalanche forecast for the season will be on Sunday, May 3rd.

Problemi valanghivi

  • Loose Wet

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

    Clear skies and near-freezing temperatures during the night have left firm snow surfaces and a thick layer of refrozen snow on many slopes this morning. Cooler temperatures and increased wind should help slow down the melting that occurs today. As a result, the window for supportable snow will last longer. Still, it is May, and cooler weather means daytime highs in the 50's above 7000 ft. and long hours of intense sunshine on all aspects so the supportable snow is unlikely to last all day. By this afternoon the overnight refreeze should melt away exposing deep wet snow on some slopes and loose wet avalanches will become possible on steep slopes. 

    Expect soft wet snow to form on E-SE-S aspects first and move to all other aspects as the day warms up. Once the snow starts getting wet and deep, it is time to avoid avalanche terrain by recreating on lower angle terrain without steep slopes above.

  • Glide Cracks

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

    Falling cornices still represent a potential problem. Large pieces could break off of these overhanging waves of snow as they melt. These blocks of snow could injure a person and may entrain more wet snow or trigger a loose wet avalanche when they impact the slopes below them.

    Cornices often break farther back from their edges than expected or at unexpected times. Staying far away from the edges of cornices and not traveling underneath cornices can help avoid this problem.

Avalanche Discussion

* Spring melt-freeze conditions exist on all aspects and at elevations across the forecast area. Melting has also resulted in many areas of bare ground on southerly aspects and in areas below 7300 ft. 

* Observations from Round Top (Carson Pass area) and Mt. Houghton (Mt. Rose backcountry) yesterday both showed a much better refreeze than in previous days. Supportable snow lasted into the afternoon even on sunny aspects. In both of these areas, sun cups and runnels have formed on the snow surface. 

* Numerous glide cracks exist where the snowpack overlies steep slabs of rock. No signs of glide avalanches have been reported.

Regioni coperte