THIS AVALANCHE ADVISORY EXPIRED ON March 24, 2016 @ 6:50 am
Avalanche Advisory published on March 23, 2016 @ 6:50 am
Issued by Steve Reynaud - Tahoe National Forest

As daytime warming occurs, moderate avalanche danger will become possible on E-SE-S-SW-W aspects at all elevations due to loose wet avalanche problems.  With overnight and continuing NE winds through today, wind slabs could exist and develop on SE-S-SW-W-NW aspects near and above treeline.  Evaluate snow and terrain carefully, identify features of concern,

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: Loose Wet
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With less cloud cover and warmer temperatures, loose wet avalanches will become more widespread today.  Most of these instabilities are expected to be in the form of roller balls or pinwheels but some could be larger and entrain most of the recent storm snow that we received.  Loose wet instabilities will be possible on E-SE-S-SW-W aspects and could also occur on NW-N-NE aspects at lower elevations that are receiving daytime warming.

Avoid slopes steeper than 35 degrees when rapid daytime warming begins.  Once the surface snow becomes wet and deep it's time to change aspects or move off and away from slopes that are 35 degrees or steeper.  Recent human or natural triggered roller balls are an indication that the snow surface is loosing strength and that larger loose wet avalanches may become possible.  Terrain traps can greatly increase the risk of these loose wet avalanches.

Avalanche Problem 2: Wind Slab
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Winds switched direction to the NE around 7pm last night and have been recorded in the 25-35mph range gusting as high as 50mph.  NE winds are forecasted to continue though today in the moderate and up to the strong range.  Wind slabs will be possible on SE-S-SW-W-NW aspects near and above treeline.  These wind slabs are expected to be small and limited to the most wind exposed terrain.

Identify and avoid steep wind loaded terrain where wind slabs exists.  Look for signs of recent avalanche activity, blowing snow, wind pillows, cornices, and human triggered snow surface cracking.  Avoid slopes steeper than 35 degrees where signs of wind slabs are present.  

recent observations

Observations were made and received yesterday from Silver Peak (Pole Creek area), Mt. Judah (Donner Summit area) and Mt. Tallac (Desolation Wilderness area).  Natural wind slab avalanche activity was reported from each area that occurred at some point towards the end of the storm cycle.  Small wind slabs were still reactive in the morning on Silver Peak with ski cuts.  Limited active wind loading was observed on Mt. Tallac with more wind transport seen on Mt. Judah.  Snowpack tests on Silver Peak and Mt Tallac showed these wind slabs gaining strength with propagation being unlikely.  Loose dry avalanches (slough) were skier triggered on Mt. Tallac in steeper below treeline terrain.  Some minor loose wet roller ball activity was noted on Mt Judah and Mt. Tallac with wet snow at all locations below 7000' by mid day.

Weather and CURRENT CONDITIONS
weather summary

High pressure will build into the area with dry conditions and warmer temperatures.  High clouds will limit some daytime warming with thicker cloud cover towards the north of the forecast region.  Highs are forecasted to be in the mid 30's to mid 40's above 7000' with NE winds 15 to 20mph gusting to 30mph.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 14 to 22 deg. F.
Max. temperature in the last 24 hours: 28 to 36 deg. F.
Average wind direction during the last 24 hours: NE
Average wind speed during the last 24 hours: 25 to 35 mph
Maximum wind gust in the last 24 hours: 50 mph
New snowfall in the last 24 hours: Trace inches
Total snow depth: 85 to 121 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Wednesday Wednesday Night Thursday
Weather: Partly cloudy. Partly cloudy. Sunny
Temperatures: 37 to 44 deg. F. 20 to 27 deg. F. 42 to 49 deg. F.
Wind Direction: NE N W
Wind Speed: 15 to 20mph with gusts to 30mph. 15 to 20mph with gusts to 30mph in the evening becoming light. 15 to 20mph with gusts to 30mph.
Expected snowfall: 0 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Wednesday Wednesday Night Thursday
Weather: Partly cloudy. Partly cloudy. Sunny
Temperatures: 34 to 41 deg. F. 20 to 27 deg. F. 38 to 45 deg. F.
Wind Direction: NE N W
Wind Speed: 15 to 20mph with gusts to 30mph. 15 to 25mph with gusts to 35mph becoming West 15 to 20mph with gusts to 30mph after midnight. 15 to 25mph with gusts to 35mph.
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