Avalanche forecast

Eastside Region

Eastern Sierra Avalanche Center
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Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

MODERATE avalanche danger exists at all elevations today. Evaluate snow and terrain carefully and use terrain choice to mitigate your exposure to potential persistent slab avalanches. Wind slabs of varying size and sensitivity will also be possible to find on all aspects near and above treeline.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2.5

    Wind slabs will vary in size and sensitivity today and may be present on all aspects near and above tree line. Lingering wind slabs on northerly and easterly terrain have the potential to be quite large and they may still be reactive to human triggers. As our current northerly winds increase in speed today, fresh wind deposits may accumulate on isolated southerly slopes as well. Exposed areas and leeward catchment zones near and above tree line deserve elevated caution. Large drifts, recent cornice growth, 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, gully features, and cross-loaded depressions.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3

    Persistent slab avalanches are becoming more difficult to trigger, predict and manage, but avalanches breaking on these lower weak layers have the potential to be very large and destructive. Persistent Slab problems challenge our patience and managing this problem requires extensive evaluation and deliberate terrain choice. Northerly and easterly aspects are of greatest concern particularly steep and rocky terrain.  Areas with shallower snowpacks, like the northern and southern reaches of the forecast area, may show a more reactive snowpack providing backcountry travelers with clear warning signs (whumpfing sounds, collapsing, shooting cracks). Conversely, in areas that received the high end of recent snow totals (the Mammoth crest) these lower weak layers may be more difficult to impact, providing fewer warning signs.  Don’t be afraid to dig in and get a look at the lower layers of the snowpack to see if old sugary snow is present in the areas you want to travel. Remember that persistent slab avalanches often propagate across and beyond terrain features that would otherwise confine surface instabilities such as wind or storm slabs and in some cases persistent slab avalanches can be remotely triggered from adjacent slopes. Give yourself a wide safety margin, be wary of hazard that may reside above you, and use terrain choice to limit your exposure.

Avalanche Discussion

As we enter a period of quite weather it will be important to remain vigilant. Field observations continue to highlight signs of instability and the challenges of spacial variability. Several large avalanches have been reported over the past few days demonstrating the destructive power of our current snowpack. Shooting cracks and large slope scale collapsing continues to show the delicate nature of our snowpack. It has been a heck of a start to our winter season and our current weather pattern will be a powerful draw to the backcountry enthusiast. However, objective evaluation and deliberate terrain choice remain prudent.

Join us this Wednesday, December 14, at 6pm at the Mountain Rambler Brewery in Bishop for the first of our Avalanche Awareness evening series. ESAC Forecaster Everett Phillips will be presenting on strategies for Maximizing the Avalanche Forecast. Can’t make it in person? You can join us virtually. We look forward to seeing you there!

 

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