THIS AVALANCHE ADVISORY EXPIRED ON March 12, 2016 @ 7:01 am
Avalanche Advisory published on March 11, 2016 @ 7:01 am
Issued by Andy Anderson - Tahoe National Forest

MODERATE avalanche danger exists on slopes steeper than 35 degrees on all aspects due to the possibility of loose wet avalanches below 8500 ft. and wind slabs on near and above treeline W-NW-N-NE-E-SE aspects above 8500 ft. Some human triggered avalanches will be possible today. Evaluate snow and terrain carefully, and identify areas where avalanche problems might exist.

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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Loose wet snow instabilities like roller balls, pinwheels, and some point releases will be possible again today on slopes steeper than 35 degrees on all aspects below 8500 ft due continued rain on snow and a lack of an overnight refreeze.  While many of these loose wet snow instabilities should remain relatively small and easy to avoid, some of the larger ones could entrain significant amounts of snow and cause problems for backcountry travelers. Steep slopes that receive rain below 8000 ft. represent the best places to find loose wet snow issues today, but these wet snow issues could also creep up to higher elevations where very wet snow falls on the surface.  

Avoid slopes with deep wet snow on them that are steeper than 35 degrees or have terrain above that is 35 degrees or steeper. Active roller balls and pinwheels indicate that loose wet snow avalanches can occur. 

Avalanche Problem 2: Wind Slab
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New snowfall today and this evening, gale force south and southwest winds, and some snow still available for transport on the windward aspects mean that new wind slabs could start forming on the snow surface of leeward slopes today. Due to the small amounts of new snow expected today and the fact that much of the snow available for transport has become very wet and heavy and hard to move, most wind slabs that do form today should remain relatively small and not extend very far away from ridgelines. Some larger more problematic wind slabs could form on leeward near and above treeline slopes above 8500 ft. where more snow falls today and where colder more easily transported snow from previous storms still exists on some of the windward aspects. Due to the more southerly nature of the winds wind slabs may form in unusual areas. Wind loaded NW-N-NE-E aspects and cross loaded W and SE aspects above 8500 ft. will represent the best places to find human triggerable wind slabs today. 

Identify and avoid steep wind loaded slopes.  Look for areas of blowing snow, cornice formation, wind scouring, and wind pillows to help determine where wind slabs exist.

recent observations

Yesterday observations on Carson Pass near Frog Lake and on Barker Pass both showed wet snow on all aspects up to at least 8500 ft. Human triggered loose wet snow instabilities like large pinwheels and roller balls occurred on steep slopes in both areas. These wet snow instabilities also existed on most aspects including the northerly ones. Rain runnels had formed on the snow surface below 7600 ft. in the Barker Pass area. In the Frog Lake area strong winds transported some snow onto the N-NE-E aspects, but observers did not report any significant wind slabs

Weather and CURRENT CONDITIONS
weather summary

Snow levels remained high yesterday and all but the highest elevations received rain during the last 24 hours. Most sensors reported .1 to .3 inches of water with a few reporting closer to .7 inches. Mixed precipitation should continue today with rain below 7500 ft, a mix of rain and snow below 8000 ft, and wet snow above 8000 ft. Areas above 8000 ft. could see up to 4 inches of snow today with another 1 to 4 inches possible this evening. This snow could also measure as little as 2 to 3 inches total and could fall as more rain than snow especially in areas below 8000 ft. The strong south and southwest winds will continue through the day. The precipitation and winds should decrease tonight. After a short break in the weather tonight and tomorrow morning the winds and cloud cover should increase as another storm moves into the region Saturday afternoon. For more details on the upcoming storms check in with the Reno NWS

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 32 to 37 deg. F.
Max. temperature in the last 24 hours: 35 to 43 deg. F.
Average wind direction during the last 24 hours: Southwest
Average wind speed during the last 24 hours: 45 to 55 mph
Maximum wind gust in the last 24 hours: 109 mph
New snowfall in the last 24 hours: Rain below 8000 ft:.1 to .3 inches | Snow above 8500 ft: up to 1 inches
Total snow depth: 71 to 99 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Friday Friday Night Saturday
Weather: Cloudy with a chance of snow and rain. Snow and rain likely this afternoon. Snow levels around 7500 ft. Cloudy with snow likely in the evening then a chance of snow showers after midnight. Mostly cloudy in the morning becoming cloudy during the day. 30% chance of snow showers during the day.
Temperatures: 37 to 44 deg. F. 25 to 31 deg. F. 35 to 41 deg. F.
Wind Direction: South Southwest Southwest
Wind Speed: 35 to 45 mph with gusts to 65 mph 15 to 25 mph with gusts to 40 mph 30 to 35 mph with gusts to 55 mph increasing to 40 to 45 mph with gusts to 70 mph in the afternoon
Expected snowfall: up to 3 in. 1 to 3 in. up to 1 in.
For 8000 ft. to 9000 ft.
Friday Friday Night Saturday
Weather: Cloudy with a chance of snow in the morning and snow likely in the afternoon. Cloudy with snow likely in the evening then a chance of snow showers after midnight. Mostly cloudy in the morning becoming cloudy during the day. 30% chance of snow showers during the day.
Temperatures: 33 to 40 deg. F. 20 to 27 deg. F. 31 to 37 deg. F.
Wind Direction: South Southwest Southwest
Wind Speed: 65 to 70 mph with gusts to 100 mph decreasing to 55 to 60 mph with gusts to 90 mph in the afternoon 30 to 40 mph with gusts to 60 mph 50 to 55 mph with gusts to 85 mph increasing to 60 to 65 mph with gusts to 100 mph in the afternoon
Expected snowfall: up to 4 in. 1 to 4 in. up to 1 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.