Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
View on map

Avalanche danger

Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
Open full map
Out of date — this forecast expired 7 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

MODERATE avalanche danger still exists in near and above treeline terrain due to shifting winds and blowing snow. Slabs of wind drifted snow (wind slabs) could exist on almost any wind-exposed slope. The avalanche danger remains LOW in wind-protected below treeline areas.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Strong NE winds have left wind slabs on N-NW-W-SW-S-SE aspects. While these lingering hard slabs may be more difficult to trigger, a person could still cause them to release from the right spot (i.e. where the slab is thinner or over a trigger point). As the winds shift back to the SW and increase today, small slabs of wind drifted snow may form on NW-N-NE-E-SE aspects. These will grow some in size as new snow forecasted for this afternoon and tonight accumulates. Avalanches that involve enough snow to bury or injure a person (D2) remain possible today. 

    Clues like blowing snow, scoured surfaces, firm hollow-sounding snow, sastrugi, drifted snow, and other wind created textures can help identify where wind slabs may exist. These exposed areas will also hold more variable and challenging snow conditions. Travel plans that focus on finding sheltered terrain are more likely to find soft unconsolidated snow.

     

    Photos: Human-triggered wind slab avalanche from Dec 27. More info here.

Avalanche Discussion

* Exposed near and above treeline terrain held wind affected snow surfaces ranging from scoured icy crusts to sastrugi to hard wind slabs to softer wind drifted snow. Observers reported seeing blowing snow along ridgelines yesterday on the Sierra Crest and in the Mt. Rose backcountry. 

* Some human-triggered cracking and test slope failures occurred in the Donner Pass and Castle Peak areas yesterday. Some minor cracking also occurred in the Slab Cliffs area. 

* In sheltered below treeline areas near Ebbetts Pass, Luther Pass, Donner Summit, and in the Mt. Rose backcountry, soft snow still existed. Observers found some surface hoar but it had already fallen over and started to deteriorate in most places.

Regions covered