Lawinenlagebericht

Eastside Region

Eastern Sierra Avalanche Center
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Lawinengefahr

Tue
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
3 · Erheblich
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Veraltet — dieser Lagebericht ist 3 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

If we receive the expected snowfall amounts, avalanche danger will rise throughout the day. Wind and new snow will create unstable conditions in leeward terrain, and avalanches can break in weak, sugary snow at the base of our snowpack. You can best manage today's hazard by avoiding travel on and beneath slopes approaching 30º. 

Lawinenprobleme

  • Wind Slabs

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

    Winds will remain strong enough to produce unstable wind drifts today as new snow continues to fall. Reactive wind slabs may also linger from this weekend's storm. Wind slabs often form on leeward slopes beneath ridgelines, and in bowls, gullies, and chutes. Look for blowing snow, textured snow surfaces, and cracking. Hollow, wind-stiffend snow is also a good indicator of wind slab formation. It is important to consider that a wind slab breaking could step down into our persistent weak layers, producing a much larger avalanche involving the entire depth of our snowpack.  

    (1/15/2024)

    30 ft shooting crack in a soft wind slab 

    Photo: Samantha Rubin

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1.5–3

    A well-developed layer of weak, sugary facets remains at the base of our snowpack. In areas where the snowpack is shallower, persistent slabs may be relatively smaller in size, but easier to trigger. In areas with a deeper snowpack, this weak layer is harder to access. However, if agitated, an avalanche on this layer could have deadly consequences.  Cracking, collapsing and whumpfing are all signs of instability. It is important to avoid trigger points such as rocks and trees, convexities, or points of steep terrain near rocky cliffs where the snowpack may be shallower. Some of these trigger points may be buried in areas with a deeper snowpack, which makes this problem even more difficult to navigate. The best way to manage this instability is to avoid traveling on and beneath slopes approaching 30º. 

    (1/20/2024)

    1 finger hard slab 2.5 feet thick over the December depth hoar. 9600 feet, northeast aspect. 

    Photo: Clancy Nelson

Avalanche Discussion

As we welcome new snow and wind today, we are worried about both surface instabilities and loading our persistent weak layers.  We are expecting to receive 6 - 10 “ of snow in the next 24 hours along the crest, and from Mammoth Lakes north. This much new snow could produce localized instabilities within the new storm snow, and at the new snow/old snow interface. Signs of reactive wind slabs have been observed in the last 48 hours, and we can expect new wind slabs to form today as well. 

We’ve been experiencing unusual snowfall patterns this season in the Sierra. Unusual snowfall patterns mean unusual avalanche problems. We are still dealing with reactive, well-defined depth hoar at the base of our snowpack. This problem is especially difficult to manage right now because the depth of our snowpack varies significantly throughout our region. You can best manage this problem by avoiding traveling on and beneath slopes approaching 30º, especially as they are loading with new storm snow and wind.

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