Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

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

MODERATE avalanche danger continues today at all elevations. Uncertainly exists in regards to the degree of loose wet avalanche problems today as well as lingering wind slab avalanche problems. Conservative decision making and conservative terrain selection are advised.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Near to above freezing air temperatures exist this morning at most mid and upper elevation locations. Transitional recent storm snow with thin melt-freeze crust exists in many areas. There is uncertainty as to how much sunshine will occur this morning and the associated amount of snow surface melt that will occur today. If last night's snow surface refreeze melts away, loose wet avalanche problems will exist again today. Increasing SW winds will slow snow surface cooling in wind exposed areas, but not in wind sheltered areas.

    Be cognizant of and conservative with specific slopes that hold surface wet snow today, especially in areas of sun exposure and wind protection.  

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1

    Storm snow instabilities have been slow to stabilize in some areas near and above treeline on NW-N-NE aspects. This is possibly due to one or more layers of graupel present within the recent storm snow in some areas. Exercise conservative terrain selection and decision making in areas where signs of recent slab avalanche activity exist, even if the avalanches appear to be several days old. The same weak layer my still be an issue.

Avalanche Discussion

A skier triggered wet snow avalanche was reported yesterday that occurred on Mt. Tallac in "The Cross". This avalanche occurred around 1 pm under warming conditions and was around 1 foot deep and 20 feet wide. As is typical with warming instability of recent storm snow, previous tracks existed on the slope prior to the avalanche occurrence. Observations made yesterday afternoon on Andesite Peak (Donner Summit area) revealed wet surface snow on all aspects up to the peak's summit at around 8,200'. Signs of loose wet instability were widespread with loose wet avalanche activity intentionally triggered on steep test slopes. Snowpit data collected yesterday on Red Lake Peak (Carson Pass area) revealed signs of ongoing instability within the recent storm snow on previously wind loaded slopes. Snowpit tests showed failures on a layer of graupel that may be associated with the recent avalanche activity in the area.

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