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 4 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Strong winds combined with a little bit of new snow today could create some areas of unstable snow in places where wind drifted snow is depositing. While the expected avalanche size today is small, exercise caution around gullies and areas near ridgetops where any blowing and drifting snow has deposited as a cohesive slab.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Winds out of the W gradually increased in speed yesterday, peaking at strong to gale force last night. Minor amounts of blowing and drifting snow from the past 24 hours combined with the possibility of a couple of inches of new snow and NW winds today will drive concerns for small areas of unstable snow on N-NE-E-SE-S-SW aspects. In most near treeline and above treeline areas where drifting snow has deposited, today's wind slabs will be small at size D1. In any areas where new snowfall amounts reach the upper end of forecast totals today, cohesive wind slabs approaching size D2 could pose a more substantial threat to backcountry travelers.

    Identify the slopes where blowing and drifting snow is accumulating and creating the possibility of unstable snow. Areas below ridgetop cornice features and along the sides of cross-loaded gully features have the greatest chance of holding unstable snow today. Evaluate these areas carefully and if in doubt, avoid them.

    (2/12/2023)

    A recent small (D1) natural wind slab avalanche, similar to what could occur today. Yuba Pass, CA

    Photo: SAC

Avalanche Discussion

Recent Observations:

  • No additional reports of new avalanches were received yesterday. Several small, size D1 wind slab avalanches occurred over the previous two days.
  • Unconsolidated snow, unaffected by previous melt lingers on shaded northerly aspects in wind protected terrain below treeline.
  • Melt-freeze crust exists on most sun-exposed slopes. 
  • About one to two feet below the snow surface, older weak layers of buried surface hoar, near-surface facets, and/or graupel remain in some areas. Observations indicate a trend of increasing stability on these layers with improved bonding and decreasing reactivity in snowpit tests.

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