Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 4 years ago.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

Highlights

People could still trigger avalanches today. Watch out for open slopes near ridges and areas with different terrain features like cliffs or gullies where wind-blown snow has piled up. Look for signs of unstable snow like recent avalanches, blowing snow, and cracking snow, and move to gentler terrain if there is any doubt about the snow's stability. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    People could still release wind slab avalanches large enough to bury them on steep wind-loaded slopes today. Wind slabs could exist on almost any aspect due to the shifting winds blowing snow back and forth across the ridges earlier this week. Some of the slabs will be dense and wind compacted. As the winds shift back to the SW and increase this afternoon, they may get strong enough to add more wind-blown snow to the NW-N-NE-E-SE aspects. In addition to the wind slabs, huge cornices have formed along many ridgelines. The largest wind slabs will exist in near and above treeline terrain, but the winds may have built a few on open lower-elevation slopes.

    Blowing snow, cornices above a slope, drifted snow, dense hollow-sounding snow, and wind-created surface textures all indicate the presence of wind slabs. Before committing to any slopes where wind slabs might exist, look for any signs of instability, like recent avalanches, shooting cracks, or unstable test results. If signs of instability or uncertainty about a slope exist, bypass that area and switch to sub-30-degree slopes without steeper terrain above. 

     

     

    (1/16/2023)

    Long shooting cracks on a cross-loaded N facing slope above the standard skin track on Mt. Judah

    Photo: Andy Anderson

Avalanche Discussion

The deep snowpack has several rain crusts buried in it. Some thin layers of weak snow may (or may not) exist around some of these crusts, but they are so buried (8 to 17 ft deep) that it is difficult to trigger them or assess them with snowpit tests. Avalanche activity that fails this deep in the snowpack remains unlikely but may not be impossible.

Recent Observations

  • While numerous wind slab and storm slab avalanches occurred earlier this week, no new avalanches got reported yesterday. 
  • Signs of lingering storm slab instability diminished significantly yesterday. Observations from Carson Pass did not find obvious signs of instability. A few short and shallow cracks occurred on Jakes Peak. Some loose dry snow sluffing occurred on Jakes Peak and steep slopes in the Mt. Rose backcountry. 
  • Surface hoar has started to form on open slopes. Tonight's snowfall could bury this surface hoar if it is not destroyed by the wind or sun. If you see these feathery snow grains standing up on slopes this afternoon, please snap a photo and submit a quick observation.
  • Thin sun crusts have started to develop on some sun-exposed slopes.

Regions covered