Avalanche forecast

Central Sierra Nevada

Sierra Avalanche Center
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Avalanche danger

Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Early this morning, moderate avalanche danger exists on all aspects and elevations due to the continuing possibility of wind slabs and storm slabs.  As sunny skies and solar radiation affect the snowpack later this morning, avalanche danger will rise to considerable on E-SE-S-SW-W aspects due to loose wet avalanches and the possibility of wet slabs.  Increasing SW-W winds throughout the day will form new wind slabs on NW-N-NE-E-SE-S aspects near and above treeline. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    3

    Winds switched to the NE overnight and are now back to the SW and increasing in speed.  Winds are forecasted to be from the SW/W in the 30 to 35mph range with gusts to 50mph in the afternoon.  With significant amounts of snow available for transport, wind slabs could form on NW-N-NE-E-SE and maybe even S aspects near and above treeline during the day.  In some areas, these winds slabs could form on top of existing wind slabs from the last couple days that have not fully bonded and gained strength.

    In the areas of direct wind loading later today, natural avalanches could become possible and human triggered wind slabs could become likely.  Identify and avoid steep wind loaded slopes.  Look for areas of blowing snow, cornice formation, wind scouring, and wind pillows to help determine where wind slabs exist.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2

    Loose wet avalanches will become likely today on E-SE-S-SW-W aspects as daytime warming occurs with intense solar radiation.  Most loose wet instabilities will be in the form of roller balls and pinwheels.  Though larger loose wet avalanches that are large enough to injure or bury a backcountry user will become possible today.

    Avoid slopes that are steeper than 35 degrees or have terrain above that is 35 degrees as solar radiation increases.  Timing is critical on solar aspects as danger can increase quickly.  Wet surface snow, active roller balls and pinwheels are indications that the snow surface is loosing strength and it's time to get off steeper terrain and change aspects.  

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2

    Wet slabs will become possible today on E-SE-S-SW-W aspects at all elevations.  Most wet instabilities today are expected to be in the form of loose wet avalanches but there is the possibility that wet slabs could occur.  These wet slabs could fail on previous wind slabs and storm slabs that have not fully bonded and gained strength or new wind slabs that are forming today.

    Today will be the first significant melt on our new storm snow.  Cloud cover could play a part this afternoon by limiting or increasing the amount of solar radiation slopes receive.  Avoid steep slopes on solar aspects.  Loose wet avalanches could occur just prior to wet slab activity. 

Avalanche Discussion

A skier triggered avalanche was reported above the Red Lake Road (Carson Pass area) yesterday around 12pm.  Crown was 1' deep and failed within the recent storm snow.  Other details are not available at this time.

Other observations from Rubicon Peak (West Shore area), Angora Peak (Echo Summit area), Echo Peak (Echo Summit area), and Elephants Hump (Carson Pass area) reported 2-4' of recent storm snow with additional snowfall in the afternoon.  In many locations shooting cracks and some snowpack tests indicated that there is still weakness within the recent storm snow.  Humid conditions with wet sticky snow below 7000' was reported. 

Regions covered