Lawinenlagebericht

Eastside Region

Eastern Sierra Avalanche Center
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Lawinengefahr

Fri
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Kernpunkte

Triggering an avalanche is more likely in leeward catchment zones near and above treeline and in places where a stiff and cohesive slab rests over weak sugary snow. Areas with more significant coverage will also be areas with heightened avalanche concerns. Shallow coverage and exposed obstacles will elevate the consequences of any avalanche involvement today.

Lawinenprobleme

  • Persistent Slabs

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

    Field observations continue to highlight weak basal facets and depth hoar at the base of the snowpack. While this poor structure dominates the forecast area, our current persistent slab problem is isolated and most likely confined to terrain features prone to wind loading, which held continuous snow coverage in November and early December. These are also areas with more substantial coverage. This means that areas with enough snow to be attractive to backcountry riders are the same areas that may contain the setup for an avalanche. If triggered, a resulting avalanche could break with little warning, involving the full depth of the snowpack. Keep in mind that being carried in an avalanche today will have elevated consequences due to the very shallow and rocky nature of our snowpack. The easiest way to avoid this problem is to stick to lower-angle terrain without overhead hazards.

    (12/24/2023) Photo: Clancy Nelson

  • Wind Slabs

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

    Fresh and thin windslabs may be reactive in leeward catchment zones near and above treeline today.  Recent field observations show that very little snow is available for transport in windward fetches. This means that recent deposits are most likely in areas where strong winds overnight were coupled with higher amounts of new snow, such as higher elevations and areas near the Sierra crest. Recent drifting, hollow upside-down feeling snow, and uneven snow surfaces are all clues that indicate nearby wind deposits. Do your own localized assessments and be suspect of terrain features that encourage drifting, such as the leeward sides of ridgelines, alpine couloirs, gully features, and cross-loaded depressions.

    (1/6/2023) Photo: Cracking in wind slabs

Avalanche Discussion

A brief storm overnight brought minimal amounts of snow to the forecast area. Most areas saw little to no new snow. The exception to this may be areas near the crest where up to 2” of snow was recorded. This snow fell during a period of strong to extreme SW winds. While this event could have added small fresh wind slabs in some areas, it may have also stiffened surface snow on leeward terrain features, creating a more connected slab for our PS problem.

While strong winds and subsequent snow deposition may have complicated our avalanche picture today, our main concern is still focused on the potential for avalanches to break full depth. It’s worth noting that our windslab concern overlaps with our persistent slab concern in distribution. This means that even a small windslab avalanche could be enough to cause a larger avalanche to break near the ground. The consequences of any avalanche involvement today are high and may result in being carried through terrain riddled with shallowly buried obstacles.  When in doubt, sticking to lower-angle slopes that have seen little wind effect is your best bet for avoiding the hazard.

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