Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

New deposits of wind-blown snow and previously formed slabs of wind-blown snow near ridges and in gullies could be unstable today. Wet snow may also slide down steep slopes at lower elevations as the day warms. If you see signs of unstable snow like recent avalanches, cracks in the snow, blowing snow, roller balls, or pinwheels, be willing to move into gentler terrain.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    People triggered more small wind slab avalanches yesterday. These will remain possible today. Slabs of wind-blown snow could exist on any aspect since the shifting winds could move snow to new locations, and old wind slabs formed by the strong ENE winds still linger near ridges, on open slopes, and in gullies. Most of these should stay small and quickly decrease in size downwind of where they form. Some could involve enough snow to bury a person, especially in places with the most efficient wind loading or where more fresh snow fell during the storm, like the Carson and Ebbetts Pass areas. 

    Cornices above a slope, blowing snow, smooth, filled-in-looking areas, and other wind-created surface textures can help identify where wind slabs exist. Recent avalanches, cracks in the snow, unstable test results, or even feeling soft snow below dense wind-pressed snow indicate that those slabs remain unstable. Traveling in sheltered terrain can reduce the chances of encountering potentially unstable wind slabs and increase the chances of finding softer, more consistent snow conditions. 

    (2/11/2023)

    Human-triggered D1 wind slab on Relay Peak. This slide had a crown of less than 1 ft in depth.

    Photo: Public

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Today's sun and warmer weather may allow enough wet snow to form on sunny slopes for some wet snow instabilities. In most spots, these will remain small and limited to pinwheels, rollerballs, and small sluffs of wet snow since only a couple of inches of snow accumulated during the recent storm. Some larger wet loose avalanches may be possible in places that received more snow, like the Carson Pass and Ebbetts Passa areas. 

    Once rollerballs and pinwheels start, the snow has become wet enough to slide downhill, and it is time to switch to lower-angle slopes or colder aspects. 

Avalanche Discussion

Recent Observations:

  • Two more human-triggered wind slab avalanches occurred yesterday. One occurred in open above treeline terrain on a WSW aspect and one in lower-elevation terrain. Both were small (D1). Widespread uneven wind-affected snow surfaces exist on slopes exposed to the winds and ridges. Expect a mix of sastrugi, wind-sculpted snow, wind-pressed snow, and wind-scoured snow in these areas.
  • Soft cold snow can still be found on shaded northerly aspects in wind-protected below-treeline terrain.
  • Melt-freeze crusts exist just below the soft new snow on many sun-exposed slopes. 
  • Below the surface, older weak layers still exist (buried surface hoar, near-surface facets, and a graupel layer) in some areas. Over the last several days, observations have shown a trend toward better bonding and increasing strength in these layers.

Regions covered