Bollettino valanghe

Eastside Region

Eastern Sierra Avalanche Center
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Pericolo valanghe

Thu
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 5 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Dangerous avalanche conditions exist, and human-triggered avalanches will be LIKELY today. Fresh and sizable wind slabs are our main concern; however, storm instabilities such as loose dry and storm slab avalanches will also be possible in sheltered and steep terrain.  CONSIDERABLE avalanche danger exists. Careful snowpack evaluation, cautious route-finding, and conservative decision-making are essential.

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Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    Expect to find fresh and sensitive wind slabs on northerly and easterly terrain near and above treeline today. Wind speeds will maintain transportable speeds as snow continues to fall. You can expect the size, sensitivity, and distribution of these wind slabs to increase as snow continues to add up this afternoon. Prior to this storm, field observations found a wide variety of surface conditions on all aspects. Surface facets and a variety of hard and slick crust layers will exacerbate the avalanche problem today.   Be suspect of terrain features that encourage drifting such as the leeward sides of ridgelines, gully features, and cross-loaded depressions. Blowing snow, recent cornice growth, drifting, stiff hollow feeling upside-down snow, and textured, uneven snow surfaces are all signs of recent wind transport. Use these clues to identify and avoid areas with recent wind deposits. 

  • Loose Dry

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    Loose-dry avalanches are likely today, particularly on steep slopes in sheltered terrain. As of 6 am this morning 10” of snow has been recorded in the Mammoth area and more is likely today. This new snow has fallen on a wide variety of old surfaces ranging from soft, unconsolidated surface facets to hard and slick crust layers. Consequently, our new snow isn’t likely to bond well to the old snow surface right away. This will make surface instabilities more sensitive than we may typically expect.  Convex rollovers and slopes over 35° in steepness are potential problem areas. When in doubt, avoid being on or underneath avalanche terrain and be cognizant of your exposure to terrain features that increase the consequences of avalanches. This includes road cuts, gully features, cliff bands, and mid-slope depressions.

     

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Strom slab avalanches may be possible today on steep slopes and in sheltered terrain. Expect this size and sensitivity of storm instabilities to increase as snow totals add up this afternoon. Do your own localized assessments as you travel in the backcountry today. Areas with more significant snowfall totals will be suspect particularly if you notice the new snow has an upside-down quality. Steep slopes over 30° and convex rollovers should be approached with caution today particularly in sheltered terrain. When in doubt it is advisable to avoid being on or underneath steep slopes. Be cognizant of your exposure to terrain features that increase the consequences of avalanches. This includes road cuts, gully features, cliff bands, and mid-slope depressions.

     

Avalanche Discussion

As is often the case here on the eastside, we have drastically different conditions from one end of the forecast are to the other. Snowpack depths are substantially deeper in areas north of Mammoth while in the southern part of the forecast area coverage is still rather thin to nonexistent.  Along this same line, snow totals from our current storm range from a trace to 10+” with the Mammoth area showing the high end of this range.  This is important to consider as you make your recreation plans as the avalanche danger is directly impacted by these different weather inputs. Conducting your own localized assessments is crucial.  Don’t let powder fever cloud your judgment today, things are likely to be sensitive as this new snow adapts to the wide variety of old surfaces.

Recent Observations

-3/9- Mammoth Area- Dust on crust, small loose dry avalanche activity, and strong winds in the Sherwins

-3/8 – Mammoth Area– Hollywood Bowl: Winds, light snow, conditions.

-3/8 – Big Pine – Red Lake to Tinemaha: Weather and snow coverage.

Regioni coperte