Lawinenlagebericht

Central Sierra Nevada

Sierra Avalanche Center
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Lawinengefahr

Wed
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 5 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

One to four inches of new snowfall over the highest elevations and rain in most other places combined with wind occurred during the past 18 hours. There is a possibility for some unstable snow where blowing snow has accumulated or where rain on snow has wetted the snow surface. Exercise caution near or below slopes where blowing snow has accumulated into drifts or where you sink more than ankle deep into wet snow.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    A few locations above about 8,000' received up to four inches of new snow, sufficient to create some new wind slabs. Blowing and drifting snow along ridgelines is expected to have deposited new slabs on top of the old snow surface that was either firm and icy or even a little sugary. While these new wind slabs are expected to be small, fairly thin, and not extend very far down slope, consequences of being caught in a small avalanche could include injury from hitting rocks.

    Identify and move cautiously around these areas where wind drifted new snow has deposited. This is most likely found above treeline and near treeline on NW-N-NE-E aspects. Any new cornice development, wind drifts, or snow surface cracking are clues to potentially unstable snow in the immediate area.

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–1.5

    Rain on a snowpack that was already weak, especially on shaded NW-N-NE aspects may allow for some unstable wet loose snow to exist today. Exercise caution near or below any areas where wet snow avalanches have already occurred or on slopes where sloppy wet snow is more than ankle deep. 

Avalanche Discussion

* 1 to 3 feet of snow exists on NW-N-NE aspects with continuous snow cover starting above about 8,000-8,500 ft. Prior to the rain and snow from the past 24 hours, the snow surface was highly variable with a mix of firm icy crusts and breakable crusts in most places.  Below about 7,800'-8,000', expect to find a mix of patchy snow cover and bare ground.

* On the NW-N-NE aspects that hold continuous snow cover, the existing snowpack is weak in many areas. During the prolonged Nov 10-Dec 5 dry spell the faceting process turned much of the middle and upper snowpack into weak sugary snow. This snowpack is in poor condition to handle new snow loading of more than 6 to 12 inches.

* Almost all SE-S-SW-W aspects are snow-free with continuous bare ground exposed.

* Surface wet snow that exists today is expected to refreeze tonight and create firm icy travel conditions for tomorrow.

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