THIS AVALANCHE ADVISORY EXPIRED ON January 9, 2016 @ 7:00 am
Avalanche Advisory published on January 8, 2016 @ 7:00 am
Issued by Andy Anderson - Tahoe National Forest

Human triggered avalanches remain possible today due to lingering wind slabs and storm slabs. MODERATE avalanche danger exists on all elevations on NW-N-NE-E-SE aspects on slopes 35 degrees and steeper. Evaluate snow and terrain carefully before committing to any slopes. 

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.

2. Moderate

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Below Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
    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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While wind slabs have become more difficult to trigger, some human triggered wind slab avalanches will remain possible today. Unsupported snow slopes above cliffs, wind loaded steep couliors, and other complex or extreme terrain will represent the best places to find fragile wind slabs, but they could also still linger on other wind loaded NW-N-NE-E slopes in near and above treeline terrain. Due to the winds shifting between south and southwest some wind slabs could also still lurk on isolated cross loaded W and SE aspects. Avalanches resulting from the failure of these wind slabs would easily involve enough snow to bury a person and could be even larger in the most heavily wind loaded areas. 

Avalanche Problem 2: Storm Slab
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As the new snow continues to consolidate, storm slabs should become more difficult to trigger. That being said, some of these storm slabs may be resting on an old snow surface that shows some evidence of becoming a persistent weak layer in a few areas. Today human triggered storm slab avalanches that fail on a lingering weaknesses in the storm snow or on the interface between the storm snow and the old snow below it still remain possible. Steep NW-N-NE facing slopes in near and below treeline terrain represent the most likely places to find lingering storm slabs and the most likely aspects where the old snow surface could start behaving more like a persistent weak layer. Some storm slabs may also remain possible on steep E facing aspects as well. Storm slabs on other aspects have become unlikely but not impossible. Storm slabs that have the ability to propagate far distances or be remotely triggered have become more unlikely, but that potential may still exist in a few isolated areas where the storm slabs rest on old snow surfaces that have started behaving like persistent weak layers.

recent observations

Yesterday small human triggered storm slab avalanches occurred on Red Lake Peak, Andesite Ridge, and on Talking Mountain. On Red Lake Peak and Andesite Ridge these slides measured about 12 inches in depth while smaller slides less than 5 inches in depth occurred on Talking Mt. All of these avalanches occurred on steep N-NE facing aspects. Reports indicate that the Andesite Ridge slide and possibly the Red Lake Peak slide occurred due to a weakness at the old snow surface just below the recent snow while the ones on Talking Mt. occurred within the recent snow. In addition to these storm slabs skier triggered loose dry sluffs/point releases also occurred on Talking Mt., Red Lake Peak, and Tamarack Peak. On more exposed wind loaded test slopes some skier triggered cracking occurred on Talking Mt. and on Tamarack Peak. Snowpit data from Tamarack Peak and Red Lake Peak showed that the snowpack has started to bond in some areas while other data (a.k.a. the avalanches mentioned above) clearly indicated that poor bonding exists in other areas. 

Weather and CURRENT CONDITIONS
weather summary

Low temperatures in the lower elevation valleys remain colder than those at the upper elevations this morning due to cold air sinking into those lower elevations. As the day warms up expect daytime highs above 7000 ft. to climb into the mid to upper 20's. Yesterday's light winds and calm weather should persist through today before a weak storm arrives tonight. Winds and cloud cover should start increasing tonight and some snow may start to fall after midnight. Light snowfall, moderate to strong southwest winds, and cold temperatures will continue through tomorrow. By the end of the day tomorrow 3 to 6 inches of new snow may have accumulated.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 12 to 19 deg. F.
Max. temperature in the last 24 hours: 20 to 28 deg. F.
Average wind direction during the last 24 hours: Southwest to northeast
Average wind speed during the last 24 hours: 5 to 10 mph
Maximum wind gust in the last 24 hours: 25 mph
New snowfall in the last 24 hours: trace to 1 inches
Total snow depth: 55 to 66 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Friday Friday Night Saturday
Weather: Mostly cloudy Cloudy with snow showers after midnight Cloudy with snow showers
Temperatures: 23 to 30 deg. F. 13 to 20 deg. F. 22 to 29 deg. F.
Wind Direction: Variable South Southwest
Wind Speed: Light 0 to 5 mph increasing to 10 to 15 mph with gusts to 25 mph after midnight 15 to 20 mph with gusts to 30 mph
Expected snowfall: 0 in. up to 2 in. 2 to 4 in.
For 8000 ft. to 9000 ft.
Friday Friday Night Saturday
Weather: Mostly cloudy Cloudy with snow showers after midnight Cloudy with snow showers
Temperatures: 20 to 27 deg. F. 11 to 18 deg. F. 18 to 25 deg. F.
Wind Direction: West Southwest Southwest
Wind Speed: 10 to 15 mph decreasing in the afternoon 10 to 15 mph with gusts to 25 mph increasing to 25 to 30 mph with gusts to 50 mph after midnight 30 to 40 mph with gusts to 60 mph decreasing to 50 mph in the afternoon
Expected snowfall: 0 in. up to 2 in. 2 to 4 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.