THIS AVALANCHE ADVISORY EXPIRED ON March 4, 2014 @ 6:30 am
Avalanche Advisory published on March 3, 2014 @ 6:30 am
Issued by Brandon Schwartz - Tahoe National Forest

Pockets of MODERATE avalanche danger remain near treeline and above treeline on NW-N-NE-E aspects on slopes 35 degrees and steeper due to lingering wind slabs. For all other areas, avalanche danger is LOW. Rain on snow may create isolated areas of loose wet avalanche activity, possible on any aspect on slopes 37 degrees and steeper.

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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Continued wind transport and subsequent wind loading has allowed for wind slabs to linger in near treeline and above treeline terrain. These slabs are high density and difficult to trigger, but human triggered avalanches remain possible in some areas on NW-N-NE-E aspects. Snowpack failure may occur anywhere from 6 inches to several feet deep within the recent new snow.

Avalanche Problem 2: Loose Wet
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If snow levels rise above 7,000' today or tonight, areas of rain on new snow will likely occur. This will allow for the possibility of small loose wet avalanches on any aspect, mainly in areas below 8,000'. Steep slope angles of 37 degrees or greater will likely be required for loose wet avalanches to initiate. Only the top one to three inches of recent new snow is expected to become involved, but deeper snow may become entrained in areas where crust does not exist within a few inches of the snow surface. 

recent observations

Observations made yesterday on Silver Peak (Pole Creek area) revealed minor evidence of lingering snowpack instability. Below treeline, ski cuts, hand pits, pole probing, and general observations did not reveal any signs of unstable slabs. Ski cuts triggered minor roller balls and pinwheels as well as one very shallow sluff that entrained 2 inches of new snow above near surface melt freeze crust. Near and above treeline, wind slabs lingered and southwest winds were observed transporting snow onto leeward aspects. Stomping on wind loaded rollovers elicited minor cracking, but did not produce wind slab failures. Snowpit tests indicated that the bond between the recent wind slab and the snow layer below continues to gain strength.

Informal observations made yesterday on snowmobiles in the Blue Lakes area (Carson Pass) noted similar conditions with blowing snow above treeline adding to existing wind slabs and no observed evidence of instability below treeline.

Weather and CURRENT CONDITIONS
weather summary

Pacific moisture is moving onshore today. Rain and snow will becoming increasingly likely across the forecast area as the day progresses. Most precipitation is expected to fall this afternoon and tonight. Snow level is expected mainly at 6,500' to 7,000', but may rise to 7,500' to 8,000' at times. New snow amounts of up to 1 inch are expected today on top of the 1 to 2 inches that accumulated yesterday. An additional 2 to 4 inches is possible tonight. Ridgetop winds will remain out of the southwest at moderate to strong in speed. A short lived break in the weather is expected tomorrow ahead of the next warm storm system expected to impact the region Wed/Thurs. 

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 25 to 31 deg. F.
Max. temperature in the last 24 hours: 30 to 35 deg. F.
Average wind direction during the last 24 hours: Southwest
Average wind speed during the last 24 hours: 30 mph
Maximum wind gust in the last 24 hours: 54 mph
New snowfall in the last 24 hours: 1 to 2 inches
Total snow depth: 46 to 59 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Monday Monday Night Tuesday
Weather: Mostly cloudy skies becoming cloudy. Scattered rain/snow showers in the morning. Isolated rain/snow showers in the afternoon. Cloudy skies with scattered showers in the evening. Rain and snow likely after midnight. Mostly cloudy skies, becoming partly cloudy.
Temperatures: 36 to 43 deg. F. 24 to 31 deg. F. 40 to 47 deg. F.
Wind Direction: Southwest Southwest West
Wind Speed: 15 to 25 mph with gusts to 40 mph. 15 to 20 mph with gusts to 30 mph. Light winds
Expected snowfall: Up to 1 in. 2 to 4 in. 0 in.
For 8000 ft. to 9000 ft.
Monday Monday Night Tuesday
Weather: Mostly cloudy skies becoming cloudy. Scattered snow showers in the morning. Isolated snow showers in the afternoon. Cloudy skies with scattered snow showers in the evening. Snow after midnight. Mostly cloudy skies, becoming partly cloudy.
Temperatures: 35 to 41 deg. F. 20 to 27 deg. F. 40 to 46 deg. F.
Wind Direction: Southwest Southwest West
Wind Speed: 30 to 40 mph with gusts to 60 mph. 20 to 30 mph with gusts to 45 mph. Gusts decreasing to 35 mph after midnight. 10 to 15 mph. Gusts to 25 mph in the morning.
Expected snowfall: Up to 1 in. 2 to 4 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.