Lawinenlagebericht

Eastside Region

Eastern Sierra Avalanche Center
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Lawinengefahr

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

Kernpunkte

LOW avalanche danger exists at all elevations.  LOW does not mean NO. Concern still exists for an unlikely but not impossible scenario where a rider could trigger a large persistent slab avalanche in steep complex terrain at all elevations. Loose-wet sloughs and rollerballs could be possible in lower elevation steep NE-N-NW facing terrain due to today’s cloud cover and relatively warm temperatures. 

*Our forecast has a new look! It might take a little getting used to, be we hope you will like it.

Lawinenprobleme

  • Persistent Slabs

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

    Sugary faceted snow exists in many places under a robust settled slab of snow from the end of January storm.  While snow-pit test results are still concerning in many areas, the snowpack has had time to adjust and it is becoming more and more unlikely that a rider could trigger an avalanche on these buried weak layers.  None-the-less, if an avalanche was triggered it would likely be large and potentially deadly.  E-NE-N-NW slopes where continuous snow existed prior to this last storm are of greatest concern, with potential on W and SE aspects as well. The northern half of the forecast zone is where more continuous old snow existed.  Complex terrain steeper than 35°, an unsupported slope, and a shallow point of snow near rocks is where an isolated trigger point for a persistent slab avalanche may exist. The potential for northerly facing slopes to warm a bit today from cloud cover could tip the balance ever so slightly towards being possible to trigger as well. What makes this a particularly tricky problem is that there aren’t warning signs, and slope cuts and stomps aren’t safe as they would likely result in the avalanche breaking above you. Expose one person at a time, and if in doubt, step it back.      

Avalanche Discussion

The combination of mostly cloudy skies and relatively warm temperatures today could lead to loose-wet concerns on steep northerly facing slopes below treeline. This will be the first time slopes facing NE-N-NW will warm significantly since the big storm, so rollerballs and loose wet sloughs could be possible in terrain greater than ~35°.  Conversely, the cloud cover and breeze today should keep upper elevation SE-S-SW facing slopes from softening too much.

At a certain point in time when the likelihood becomes low to trigger a persistent slab avalanche, forecasters wrestle with the decision to drop the danger on persistent slab problem for a few reasons: 1) A certain degree of uncertainty almost always exists especially across such a large landscape that the forecast covers. 2) A resulting avalanche would likely be large and consequential. 3) We don’t want to keep too much attention on a very unlikely problem, as that will take away from the attention it deserves when it is more concerning. To be transparent, that is the wrestling that has been taking place amongst the ESAC forecasters the last few days. While test results are becoming less concerning in some areas, they are still propagating energetically in other areas (see recent profile below from Punta Bardini) and are likely to continue to do so for a while. Test results are just one piece of the puzzle though. It is important for you to put your own thought and analysis in deciding what terrain to ride. 

RECENT OBSERVATIONS:

-2/7 – Mammoth – Sunny aspects and old Hollywood crown

-2/7 – Bishop Creek: Variable conditions

-2/6 – Mammoth – Punta Bardini: Warming southerlies, tests still propagating in facets on northerlies. 

-2/6 - June – Negatives: Wind effects, old avalanches.

-2/6 – Rock Creek – Witcher Creek: Thin snowpack, warming snow.

*Scroll up and click on “Observations” tab to see listing of past 20 observations, or click on the “Resources” menu --> “ESAC Observations” to see listing of all observations.

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