Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 3 years ago.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

Highlights

Above freezing air temperatures around the clock combined with cloud cover are making some small surface wet snow avalanches possible, mainly at mid to upper elevations. Otherwise, persistent deeper instability in the snowpack is keeping large slab avalanches possible in isolated areas. Keep safety margins as wide as possible today. Any isolated slab avalanches that occur could easily be deeper and wider than expected.

Avalanche problems

  • Persistent Slabs

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

    Persistent weak layers have been quiet for the past few days with no new avalanches, snowpack collapses, or cracking reported. Snowpit data continues to point to the potential for isolated instability on the Jan. 2 (surface hoar/facets/crust) and the Dec. 19 rain crust and basal depth hoar on the ground. These weak layers are generally found between 2 and 6+ feet deep in the snowpack. This puts us in the undesirable zone of isolated large avalanches possible.

    Encountering obvious signs of instability is unlikely at this time. If you trigger an avalanche today, it will most likely be an unexpected event.  Move through terrain with the mindset that triggering is most likely to occur somewhere where the overlying slab is thin such as around the edges of wind loaded areas or near rocks that that bring the weak layer closer to the snow surface. A slope that avalanches today could easily have previous tracks on it. Keep your margins of safety as wide as possible thinking that an avalanche will break wider and run further downslope than is common for the terrain you are in.

    (1/15/2024)

    Large natural avalanche between Lincoln and Anderson Peak-thought to have occurred on Sat Jan 13.  See the size of the crown relative to the people.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Air temperatures have been above freezing around the clock for the past 20 hours or more in most locations around the forecast area. Cloud cover has allowed surface wet snow to form in normally shaded, colder terrain. Minor surface wet snow instabilities are possible on steep slopes on any aspect. Rain crust that existed on the snow surface in some areas may or may not have melted. Areas at mid to upper elevations where new snow exists above the rain/snow line are more of a concern for this avalanche problem. Most of the instability is expected in the form of roller balls and pinwheels. Small wet loose avalanches could be triggered by backcountry travelers in steep terrain.

Avalanche Discussion

The Jan. 16-17 storm rained up to at least 8500', if not higher.  Up to 4'' of heavy wet snow accumulated in some areas of the forecast region either on top of this rain crust or at the higher elevations above 8500-9000'.  Exposed rain crust could make for challenging travel conditions in terrain below about 8000-8500' in any areas where it remains firm.  Limited amounts of snow are available for transport today making new wind slab formation unlikely despite today's increasing winds.

Regions covered