Avalanche forecast

Eastside Region

Eastern Sierra Avalanche Center
View on map

Avalanche danger

Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
Open full map
Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

In isolated areas, there is a lingering chance you could trigger large avalanches breaking on old snow and crusts in the upper snowpack. These are most likely where there’s no surface crust preventing you from impacting buried weak layers. Small wind slabs could pose a hazard in leeward terrain. You can manage uncertainty by using simpler terrain, lower slope angles, and limiting your exposure to overhead hazards like cornices. 

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–3

    Weak faceted snow and melt-freeze crusts exist at various depths in the upper snowpack. While avalanches are possible in isolated areas, we are seeing a decrease in signs of instability. Surface crusts below treeline have made initiating a failure less likely at lower elevations. The majority of avalanches failing on these layers occurred near treeline, which is where snowpack tests continue to show the potential for human triggering. Feedback - like whumpfs and shooting cracks - may be spotty and unreliable. If triggered, persistent slab avalanches can propagate beyond terrain features. They can be triggered from below or from flatter terrain adjacent to steep slopes. You can manage uncertainty by maintaining a healthy distance from convexities, wind-loaded terrain features, and suspect slopes. Large natural triggers, like cornice fall, are something to consider if you travel under slopes with big wind lips overhead. 

    (3/31/2023)

    Large remote triggered avalacnhe in V-Bowl, Lee Vining area, 9000' BTL, 3/31/23

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5

    A few inches of new snow and gusty winds could build fresh drifts in leeward terrain. Specific features of concern include steep slopes below ridgelines, the sidewalls of gullies, and cross-loaded depressions. Watch for blowing snow and cracking in dense, hollow drifts as clues that wind slabs may be unstable in your area. Even small avalanches can have big consequences in extreme terrain or above terrain traps. 

    (4/2/2023)

    Sensitive cornices triggering small wind slabs on the slope below

Avalanche Discussion

Uncertainty in today's forecast surrounds the sensitivity and distribution of the persistent slab problem, especially in alpine terrain. Faceted grains around crusts in the upper snowpack have been gaining strength in some areas. Snowpack tests near treeline continue to show potential for human-triggering of these facet/crust combos buried 1 to 3 feet below the surface. Surface melt-freeze crusts below treeline have made the problem more isolated at lower elevations. 

Though the last confirmed avalanche failing on old snow was on 3/31, avalanches that released during a wind event on 4/2 and 4/3 propagated widely, or were triggered remotely, suggesting that they may have involved persistent weak layers. 

In isolated areas where snowfall reaches the upper end of the forecast today, gusty southwest wind may deposit small slabs that could be a hazard in extreme terrain or above terrain traps. Large cornices loom over typically leeward slopes and the roots of some have been cracking. Limiting your exposure to those kinds of wind-deposited hazards is always good practice. 

Cooler temperatures, strong wind, and cloud cover will help keep the upper snowpack from thawing deeply today. It will be a different story as high pressure causes temperatures to climb above seasonal averages under clearing skies. Water percolating down to buried weak layers could cause rising avalanche danger in the coming days. 

Regions covered