THIS AVALANCHE ADVISORY EXPIRED ON February 13, 2017 @ 6:40 am
Avalanche Advisory published on February 12, 2017 @ 6:40 am
Issued by Steve Reynaud - Tahoe National Forest

Moderate avalanche danger exists in near treeline and above treeline terrain due to wind slab avalanche problems.  Human triggered wind slab avalanches remain possible today.

2. Moderate

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Above Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

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Near Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

1. Low

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Below Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
    Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Wind Slab
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    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Wind slabs will be possible on SE-S-SW-W-NW-N aspects in near treeline and above treeline terrain as strong NE/E winds continue through today.  Several avalanches were reported yesterday due to large amounts of wind transport and slab development.  Large cornices continue to exist along ridelines and peaks and should be avoided.

Look for blowing snow, cornice formation, wind pillows, and snow surface scouring as clues to where wind slabs are developing.  Avoid steep wind loaded terrain.

recent observations

Observations were received from Powderhouse Peak (Luther Pass area), Blue Lakes (Carson Pass area), Mt. Rose Wilderness and Incline Lake Peak (Mt. Rose area), Schallenberger Ridge and Andesite Peak (Donner Summit area), and Shirley Canyon (Squaw Valley area).  All areas showed strong to gale force NE winds throughout the day with large amounts of wind transport occurring near and above treeline.  Human triggered wind slab avalanches were reported at Incline Lake Peak, Mt. Rose Wilderness, and Blue Lakes.  Signs of instabilities were observed at most locations with heavy wind transport, shooting cracks in wind loaded terrain, and test slope avalanche failures.  Dense recent storm snow exists in below treeline terrain.

Weather and CURRENT CONDITIONS
weather summary

Warming temperatures will begin today with dry conditions forecasted through Wednesday.  Strong NE winds above 8000' will continue through this morning.  These winds should subside sometime during the late morning/early afternoon timeframe.  Another storm cycle is forecasted to begin on Thursday that could last through the weekend and well into the following week.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 18 to 22 deg. F.
Max. temperature in the last 24 hours: 33 deg. F.
Average wind direction during the last 24 hours: NE to E
Average wind speed during the last 24 hours: 30 to 50 mph
Maximum wind gust in the last 24 hours: 79 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 125 to 146 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Sunday Sunday Night Monday
Weather: Sunny Clear Sunny then becoming partly cloudy.
Temperatures: 37 to 42 deg. F. 17 to 25 deg. F. 41 to 46 deg. F.
Wind Direction:
Wind Speed: Light winds. Light winds. Light winds.
Expected snowfall: 0 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Sunday Sunday Night Monday
Weather: Sunny Clear Sunny then becoming partly cloudy.
Temperatures: 37 to 42 deg. F. 20 to 25 deg. F. 41 to 46 deg. F.
Wind Direction: E E
Wind Speed: 15 to 20mph. Gusts to 55mph decreasing to 45mph in the afternoon. 10 to 15mph in the evening becoming light. Gusts up to 30mph. Light winds. Gusts up to 30mph in the afternoon.
Expected snowfall: 0 in. 0 in. 0 in.
Disclaimer

This avalanche advisory is provided through a partnership between the Tahoe National Forest and the Sierra Avalanche Center. This advisory covers the Central Sierra Nevada Mountains between Yuba Pass on the north and Ebbetts Pass on the south. Click here for a map of the forecast area. This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.

For a recorded version of the Avalanche Advisory call (530) 587-3558 x258