Avalanche forecast

Eastside Region

Eastern Sierra Avalanche Center
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Avalanche danger

Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Poor snowpack structure continues to be the main concern, especially in shallower areas with less than 4 ft of total snow. Avoid thin spots that are potential trigger points, and limit exposure with lower consequence terrain.

Avalanche problems

  • Persistent Slabs

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

    A persistent weak layer (PWL) of faceted snow exists at the base of the snowpack throughout the forecast area.  Persistent slabs can be triggered from a distance, below, above, or adjacent to avalanche start zones. If triggered, they can connect terrain features and pull snow back from surrounding lower-angle terrain. The areas of greatest concern are those in which the weak layer is within one meter (~ 3 feet) of the snow surface. Uncertainty is high around the sensitivity of the 12/01 PWL.  The best strategies for managing persistent slabs are building a wide margin of error into your tour plan and using conservative terrain choices to manage uncertainty.

    Persistent Slab avalanche that released in steep rocky start zone with shallow snow cover.

Avalanche Discussion

The last reported avalanches occurred during periods of loading with new snow and wind at the end of the storm a week ago. The persistent slab structure has not gone away, but triggering a slab has become incrementally less likely each day without a new load on the snowpack.  Fewer signs of unstable snow, such as cracking and whumpfing were reported in the last 24 hours. The persistent slab is most concerning where the weak layer is less than 1 meter from the snow surface. Terrain features where triggering may be more likely include areas of shallow snow at the margin of thicker slabs, slope angles 35 degrees or greater, and unsupported start zones such as those that roll over into cliffs or steeper terrain. 

Cold temperatures in the past weak have caused surface snow to facet and lose strength. Be aware of the potential for loose dry avalanches in very steep terrain.

Regions covered