Lawinenlagebericht

Central Sierra Nevada

Sierra Avalanche Center
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Lawinengefahr

Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
Veraltet — dieser Lagebericht ist 6 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Persistent slab and wind slab avalanche problems remain possible today.  MODERATE avalanche danger will exist at all elevations.  Unstable snow continues to exist in some areas of the forecast region.

Lawinenprobleme

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    2–3

    The weak layers in our snowpack have started to gain strength and adjust to the new snow load in many locations.  Unfortunately, the process of the Dec. 11 persistent weak layer improving and gaining strength is not the same at all locations.  While some areas are pointing to improving stability, others are showing active whumpfing and unstable snowpack test results.  2 large natural avalanches were reported that are thought to have occurred during the storm on Monday and potentially failed on the Dec. 11 PWL.  Many areas throughout the forecast region at mid to high elevations are developing deeper and stronger snowpacks.  Locations at lower elevations and in some parts of the southern forecast area have shallower and weaker snowpacks.  These areas that are still shallow with a well developed Dec. 11 weak layer remain the greatest concern.  This will make it more important to collect snowpack information from your specific area and to look for signs of instabilities.  

    Could a large persistent slab avalanche still occur?  Yes.  Are conditions going to continue to improve over the days ahead?  Yes.  Conservative terrain choices are still recommended while traveling in the backcountry until this weak layer becomes unreactive.  Due to the large size, potential remote triggering, and unpredictable nature of persistent slabs, limiting exposure to this avalanche problem is warranted.    

  • Wind Slabs

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

    The wind slabs that formed during the Monday storm have continued to gain strength.  Increasing SW winds today will allow some additional snow transport and new wind slabs to develop on NW-N-NE-E-SE aspects in near and above treeline terrain.  New small wind slab development could develop where available snow for transport exists.

    Look for blowing snow, new cornice development, and wind pillows as clues to where new wind slabs may be forming.  

Avalanche Discussion

*  Whumpfing, cracking, and unstable snowpack test results were reported from Blue Lakes to Indian Valley (Carson Pass to Ebbetts Pass area).  All of these signs of instabilities were occurring on the Dec 11 PWL.

*  Large natural avalanches were reported from Dicks Peak (Desolation Wilderness area), and Hawkins Peak (Carson Pass area).  Limited information in known at this time.

*  Mt. Judah (Donner Summit area), and Carpenter Ridge (Independence Lake area), and Waterhouse (Luther Pass area) all showed improving snowpack stability.

Abgedeckte Regionen