THIS AVALANCHE ADVISORY EXPIRED ON December 23, 2017 @ 6:55 am
Avalanche Advisory published on December 22, 2017 @ 6:55 am
Issued by Brandon Schwartz - Tahoe National Forest

Avalanche danger is LOW for all elevations and aspects. Small wind slabs exist in a variety of locations near and above treeline with human triggering unlikely. Look for and identify isolated areas of potential instability.

1. Low

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Above Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1. Low

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Near Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1. Low

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Below Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
    Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Avalanche Problem 1: Wind Slab
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    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
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    Very Large
    Large
    Small

SW storm winds followed by gale force NE winds have once again created a mix of firm scoured snow surfaces interspersed with areas of recently formed wind slab on a variety of aspects near and above treeline. Winds shifted back to the SW last night, but are expected to move only minor amounts of snow during the strongest gusts. Difficult to trigger hard wind slabs will remain today on a variety of aspects near and above treeline. Potential avalanche size is expected at D1 to D1.5.

Consequences of a small human triggered avalanche could be magnified substantially if a person is carried into rocks or trees, over a cliff, or into a terrain trap. Use the equipment and travel techniques associated with normal caution to help minimize consequences if caught in an avalanche.

recent observations

* Newly formed wind slabs were observed yesterday near and above treeline in the Donner Summit, Mount Rose, and Carson Pass areas. Sensitivity to triggers ranged from unreactive to stubborn.

* Significant wind effects were noted in some areas below treeline.

* On a regional scale, the greatest snow coverage exists above 8,000' along the Mount Rose Hwy and in Sierra Crest locations north of Emerald Bay. Overall less snow cover exists south of Emerald Bay, but is generally usable above 8,500'.

Weather and CURRENT CONDITIONS
weather summary

High level cloud cover and moderate speed SW winds are expected today and tomorrow as weather systems pass by to the NE of the forecast area. Air temperature inversion conditions are in place with morning low air temperatures in the teens to 20s on the mountain valley floors and in the low to upper 30s at the mid and upper elevations on surrounding peaks. Warming at the mid and upper elevations is forecast for today and tomorrow with maximum daytime air temperatures above 7,000' reaching into the 40s for many locations.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 31 to 38 deg. F.
Max. temperature in the last 24 hours: 32 to 38 deg. F.
Average wind direction during the last 24 hours: ENE shifting to SW
Average wind speed during the last 24 hours: ENE 45 mph | SW 18 mph
Maximum wind gust in the last 24 hours: ENE 91 mph | SW 29 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 17 to 34 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Friday Friday Night Saturday
Weather: Partly cloudy skies. Mostly cloudy skies. Mostly cloudy skies.
Temperatures: 39 to 44 deg. F. 24 to 29 deg. F. 41 to 46 deg. F.
Wind Direction: W W W
Wind Speed: 10 to 15 mph with gusts to 30 mph. 10 to 15 mph. Light winds increasing to 10 to 15 mph with gusts to 30 mph in the afternoon.
Expected snowfall: 0 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Friday Friday Night Saturday
Weather: Partly cloudy skies. Mostly cloudy skies. Mostly cloudy skies.
Temperatures: 35 to 40 deg. F. 26 to 31 deg. F. 38 to 43 deg. F.
Wind Direction: W W NW
Wind Speed: 10 to 15 mph with gusts to 45 mph. 15 to 25 mph with gusts to 50 mph. 20 to 30 mph with gusts to 50 mph.
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