THIS AVALANCHE ADVISORY EXPIRED ON February 23, 2016 @ 6:45 am
Avalanche Advisory published on February 22, 2016 @ 6:45 am
Issued by Brandon Schwartz - Tahoe National Forest

Early this morning, LOW avalanche danger exists for all elevations and aspects. Small wind slabs may form today near and above treeline on SE-S-SW-W-NW aspects. Areas of MODERATE avalanche danger may form in response to daytime warming mainly on E-SE-S-SW-W aspects on slopes 35 degrees and steeper due to the possibility of loose wet avalanches. Isolated loose wet instability may occur in some areas on NW-N-NE aspects as well.

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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The surface snow will continue to warm, slowly transitioning from recent storm snow to eventually become well established supportable melt-freeze snow at a later date. During this transition, an upper snowpack structure of surface wet snow on top of yet to transition drier recent storm snow will be prone to human triggered loose wet avalanches. Most instability is expected to take on the form of roller balls and pinwheels. The vast majority of instability is expected to occur on E-SE-S-SW-W aspects. Isolated instability may occur in sun exposed areas on low to mid elevation NW-N-NE aspects as well.

Avoid the premature search for "corn snow" while the upper snowpack remains in a transitional state. Use quick hand pits to identify surface wet snow on top of colder recent storm snow that has yet to undergo melt-freeze. Slopes steeper than 35 degrees where this near surface snowpack structure exists are best avoided once a couple inches or more of surface wet snow are present. Human triggering of roller balls and pinwheels approaching or exceeding 1 foot in diameter are indicators that loose wet avalanche activity is possible.

Avalanche Problem 2: Wind Slab
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Increasing NE winds today are expected to create some areas of blowing snow and subsequent wind slab formation near and above treeline on SE-S-SW-W-NW aspects. Slab size is expected to be small, but could be problematic in the most heavily wind loaded areas. Carefully evaluate areas of active wind loading for the size and depth of new wind slab formation before committing to steep terrain.

recent observations

Observations were made and recieved yesterday from Meadow Lake (Independence Lake area), Negro Canyon and Donner Peak (Donner Summit area), and Becker Peak (Echo Summit area). Similar snowpack conditions were reported with no signs of instability observed within the recent storm snow on northerly aspects. Sun exposed flat to southerly aspects held surface wet snow on top of dry recent storm snow that had yet to under melt-freeze. A few natural and human triggered roller balls were observed in some of the warmer mid elevation areas. Variable snow surface conditions were a common theme especially at the low and mid elevations with a range from cold and dry unconsolidated, to highly wind effected, to wet.

Weather and CURRENT CONDITIONS
weather summary

High pressure is building over the forecast area. Sunny skies and above average air temperatures are forecast for today. Ridgetop winds have shifted from SW to NE this morning and are light to moderate in speed. Moderate speed N to NE winds are expected today, becoming strong in speed tonight into tomorrow morning. Remote sensors are reporting below freezing air temperatures at 6 am this morning for all elevations across the forecast area. Maximum daytime air temperatures for areas above 7,000' are expected to reach the mid 30s to upper 40s today. Continued warming at the mid and upper elevations is forecast for tomorrow.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 24 to 31 deg. F.
Max. temperature in the last 24 hours: 44 to 48 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 16 mph
Maximum wind gust in the last 24 hours: 30 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 60 to 92 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Monday Monday Night Tuesday
Weather: Sunny skies. Clear skies. Sunny skies.
Temperatures: 41 to 48 deg. F. 25 to 30 deg. F. 45 to 51 deg. F.
Wind Direction: NW to N N to E E
Wind Speed: 10 to 15 mph with gusts to 25 mph. 10 to 20 mph with gusts to 30 mph. 10 to 15 mph with gusts to 25 mph in the morning, becoming light.
Expected snowfall: 0 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Monday Monday Night Tuesday
Weather: Sunny skies. Clear skies. Sunny skies.
Temperatures: 34 to 41 deg. F. 30 to 33 deg. F. 38 to 45 deg. F.
Wind Direction: N N to NE NE shifting to W
Wind Speed: 15 to 25 mph with gusts to 40 mph. 20 to 35 mph with gusts to 50 mph, increasing to 25 to 40 mph with gusts to 60 mph after midnight. 20 to 30 mph with gusts to 50 mph, shifting and decreasing to 10 to 15 mph in the afternoon.
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.