THIS AVALANCHE ADVISORY EXPIRED ON March 28, 2014 @ 6:45 am
Avalanche Advisory published on March 27, 2014 @ 6:45 am
Issued by Brandon Schwartz - Tahoe National Forest

Avalanche danger is MODERATE on all aspects at all elevations on slopes 35 degrees and steeper due to the presence of established wind slabs and the possibility of loose wet and storm slab avalanches.

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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Recently formed unstable wind slabs that contributed to natural and human triggered avalanche activity yesterday remain a concern today. Recent wind loading and ongoing wind transport has allowed for wind slabs up to several feet thick to form near treeline and above treeline on NW-N-NE-E-SE aspects. Human triggered avalanches remain possible today in recently wind loaded areas. In the more heavily wind loaded areas, avalanche size will easily be large enough to bury or injure a person.

Avalanche Problem 2: Loose Wet
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As cloud cover decreases today and sun breaks occur, natural and human triggered loose wet avalanches will become possible in sun exposed areas on E-SE-S-SW-W aspects. Roller balls initiating from snow falling off of rocks and trees or from human activity could progress to a loose wet avalanche. Involvement of terrain features such as cliffs and terrain traps could greatly increase the consequences of becoming caught in a small loose wet avalanche.

Avalanche Problem 3: Storm Slab
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Storm slabs may exist below treeline on all aspects in areas that held snowcover prior to the current storm cycle. High intensity snowfall yesterday afternoon into last night may have allowed for weak layers to form within the storm snow. Human triggered cracking in wind protected areas below treeline today is an indication of unstable storm slabs in the immediate area. 

recent observations

Observations made yesterday on Tamarack Peak (Mount Rose Backcountry), on Andesite Ridge (Donner Summit area), and along the Frog Lake Cliffs (Carson Pass area) showed that snowpack instability was greatest along the Sierra Crest. On Andesite Ridge and along Frog Lake Cliffs, skier triggered cracking and small wind slab avalanches were observed on N-NE-E aspects near and above treeline during the mid day and early afternoon hours. A report was received of a small natural wind slab avalanche that occurred yesterday evening on Wildflower Ridge on the north side of Mt. Judah (Donner Summit area). The avalanche occurred on an ENE aspect around 7,700' in near treeline terrain that traditionally receives very heavy wind loading.

Weather and CURRENT CONDITIONS
weather summary

A break in the weather will occur today and much of Friday before the next storm system impacts the forecast area Friday night and Saturday. New snow amounts above 7,000' from the last 24 hours are 5 to 11 inches. Much of that snowfall, 4 to 8 inches worth fell during the last 12 hours. This brings the 2 day storm total up to 9 to 19 inches with the greatest accumulations along the Sierra Crest. For today, the forecast calls for cloudy skies becoming mostly cloudy with scattered snow showers. Additional new snow amounts should be minimal at a trace to 2 inches. Continued strong southwest to west winds are expected this morning, decreasing to moderate/strong in speed this afternoon. Maximum daytime air temperatures are expected to reach the mid 20s to mid 30s today for areas above 7,000'.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 20 to 24 deg. F.
Max. temperature in the last 24 hours: 27 to 31 deg. F.
Average wind direction during the last 24 hours: Southwest
Average wind speed during the last 24 hours: 40 mph
Maximum wind gust in the last 24 hours: 64 mph
New snowfall in the last 24 hours: 8 to 11 inches
Total snow depth: 38 to 54 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Thursday Thursday Night Friday
Weather: Cloudy skies becoming mostly cloudy. Scatteres snow showers. Mostly cloudy skies with a chance of snow showers. Cloudy skies with a slight chance of snow showers.
Temperatures: 29 to 36 deg. F. 20 to 27 deg. F. 35 to 42 deg. F.
Wind Direction: Southwest Southwest Southwest
Wind Speed: 25 to 35 mph with gusts to 50 mph, decreasing to 15 to 20 mph with gusts to 35 mph in the afternoon. 15 to 20 mph with gusts to 35 mph. 15 to 25 mph with gusts to 35 mph.
Expected snowfall: Trace to 1 in. Trace in. 0 to trace in.
For 8000 ft. to 9000 ft.
Thursday Thursday Night Friday
Weather: Cloudy skies becoming mostly cloudy. Scatteres snow showers. Mostly cloudy skies with a chance of snow showers. Cloudy skies with a slight chance of snow showers.
Temperatures: 24 to 31 deg. F. 19 to 24 deg. F. 30 to 35 deg. F.
Wind Direction: West Southwest Southwest
Wind Speed: 40 to 55 mph with gusts 60 to 80 mph, decreasing to 30 to 40 mph with gusts to 55 mph in the afternoon. 30 to 40 mph with gusts to 55 mph, decreasing to 20 to 30 mph with gusts to 45 mph after midnight. 20 to 30 mph with gusts to 45 mph.
Expected snowfall: Trace to 2 in. Trace in. 0 to trace 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.