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

In sintesi

MODERATE avalanche danger will form on slopes steeper than 35 degrees on E-SE-S-SW-W aspects at all elevations and may form on some sun-exposed near and below treeline NW-N-NE aspects as daytime warming makes loose wet avalanches possible again today. Clues like sinking into wet snow above your boot tops or small point releases, roller balls, or pinwheels can help determine when to move to more frozen aspects, onto lower angle slopes, or to switch to a different afternoon activity.

Problemi valanghivi

  • Loose Wet

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

    The recent snow still has not experienced enough melt-freeze cycles to form good drainage channels in many areas. More sunshine, warmer temperatures, and less wind today mean that loose wet avalanches will become possible as last night's refreeze melts leaving a layer of wet snow sitting on top of old frozen crusts. These old frozen crusts make efficient bed surfaces for the wet snow to slide on. Like yesterday some of the loose wet avalanches that occur today could entrain enough snow to cause problems for backcountry travelers especially in areas where the loose wet avalanches involve terrain traps. Slopes steeper than 35 degrees on sun-exposed E-SE-S-SW-W aspects at all elevations will hold the best potential for loose wet avalanches since they should experience the most warming, but some of the near and below treeline NW-N-NE aspects could also see enough sun for some wet snow instabilities to form. Expect to find deeper wet snow and larger wet snow issues in the Mt. Rose backcountry where the most snow fell during the recent storm. In areas along the Sierra Crest south of Highway 50 where less recent snow exists, the wet snow issues should remain smaller and entrain less snow. Wet snow instabilities in areas north of Highway 50 along the Sierra Crest and on the east side of Lake Tahoe south of Mt. Rose should fall somewhere between the other two zones, and the size of loose wet snow instabilities will depend on the amount of recent snow that exists in a specific area.

    Sinking into wet snow above your boot tops and small surface instabilities like roller balls, pinwheels, or point releases can provide clues that enough wet snow has formed for larger loose wet avalanches to become an issue. Moving to more frozen slopes or onto lower angle slopes off and away from slopes 35 degrees or steeper before deep wet snow exists on a slope represents a wise choice for today. Terrain traps like gullies, creeks, and cliffs can greatly increase the risk of any size loose wet avalanches.

Avalanche Discussion

Yesterday on the Fireplug in the Mt. Rose backcountry, wet snow had formed above frozen crusts on any sun exposed slopes where recent snow existed by mid morning. Skier triggered loose wet slides occurred on steep NE facing slopes and on E-SE facing test slopes. Upper elevation northerly aspects held scoured crusts and more sheltered lower elevation northerly slopes had breakable crusts on the surface in most places with a few isolated patches of soft cold snow remaining in some areas. 

Regioni coperte