Lawinenlagebericht

Central Sierra Nevada

Sierra Avalanche Center
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Lawinengefahr

Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Veraltet — dieser Lagebericht ist 7 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

MODERATE avalanche danger will exist due to a combination of wind slab and storm slab avalanche problems.  Unusual storm slab conditions continue with buried surface hoar beneath the recent storm snow.  Human triggered avalanches are possible in specific areas today.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1

    Increasing winds today will mean blowing snow and new wind slab formation.  Unstable wind slabs continued to exist in some areas yesterday and new ones will form on top of them today.  Plenty of soft snow remains on most ridgetop areas to be transported by the forecasted strong SW winds today.  Light snow flurries will add to the snow available for transport into tonight.

    Look for active wind loading in the form of blowing snow and cornice formation.  Problematic wind slabs are expected in near and above treeline areas where winds can transport snow effectively. 

  • Loose Dry

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    2

    Unusual storm slab conditions exist in our area.  The recent storm snow from Dec. 6-8 sits on top of a layer of buried surface hoar that has been found in many locations throughout the forecast region.  This weak layer is remaining reactive much longer than our typical storm slabs.  A boarder triggered avalanche yesterday resulted in a full burial that failed on this buried surface hoar layer.  Problematic storm slabs are 1-2’ deep, located on NW-N-NE-E aspects above 8000’, in open below treeline terrain, where this buried surface hoar layer exists.

    While general snowpack stability may seem good in many areas, storm slab avalanches could still be human triggered.  Avalanches could have wide propagation, be remotely triggered, fail mid slope, and potentially show no other signs of instability in the area.  Look out for common trigger points, especially convex roll overs.  Avoid being connected to larger exposed avalanche slopes or complex terrain. 

Avalanche Discussion

* A boarder triggered avalanche resulted in a full burial in the Castle Peak area yesterday.  The avalanche occurred mid slope at 8300', was remotely triggered, and had wide propagation.  The weak layer was identified as buried surface hoar beneath Dec. 6-8 storm slab.

* A recent natural wind slab avalanche was seen on Red Lake Peak (Carson Pass area) yesterday.  Many signs of recent wind transport were observed with easy cracking and failing of wind features in wind loaded terrain.

* Previous natural avalanche activity was reported from the Castle Peak/Basin Peak area that had the characteristics of avalanches with a buried surface hoar weak layer.

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