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.

Snow showers continue over the forecast area as the last of the storm systems for this week exists the region. Remote sensors are reporting new snow amounts over the past 24 hours of 7 to 8 inches in most areas along the Sierra Crest. Accumulations up to 11 inches are reported along the Sierra Crest north of Lake Tahoe. Around 3 inches of new snow accumulated in the Carson Range over the past 24 hours. This brings total new snow amounts for the past week up to 3 to 6 feet, depending on location. Ridgetop winds shifted to the east yesterday morning and were moderate to strong in speed from 8 am to 6pm. Winds shifted to the southwest yesterday evening and remained moderate to strong overnight. Air temperatures maintained a cooling trend from 8pm last night through this morning, when the bulk of the overnight snowfall occurred.

Observations:

Observations made yesterday in Negro Canyon (Donner Summit area) in near treeline terrain at 7,240' on a E aspect 20 degree slope revealed limited signs of instability in areas unaffected by wind. Previously observed instabilities within the storm snow and small faceted crystals on top of the January 11 crust appeared to have stabilized. In more wind affected areas, skier triggered cracking that occurred within the top 1 foot of the snowpack and propagated less than 5 feet away from the trigger point was observed (pit profile, photos, and video). This matched well with observations made in the Upper South Fork of Cold Stream (Cabin Creek/Deep Creek area) in near treeline and below treeline terrain between 7,000' to 8,000' on NW-N-NE-E aspects (photo, more info). No new avalanche activity was reported to have occurred yesterday, but we were unable to make backcountry observations above treeline.

Avalanche Concerns:

Avalanche concerns for today are focused on unstable slabs in wind affected areas both above and below treeline. The greatest areas of instability are expected to occur near and above treeline on the most heavily wind loaded NW-N-NE-E aspects. Smaller areas of instability are expected in open wind loaded areas below treeline. After yesterday's east winds, plenty of snow remains available for wind transport by last night's and today's southwest winds. The best window for natural avalanche activity occurred last night. However, the combination of continued SW winds and snow available for transport will allow natural avalanches to remain possible today in isolated areas that receive continued wind loading. In less wind affected areas, small slabs and human triggered sluffs are expected in steep terrain.

The bottom line:

Near and above treeline, pockets of CONSIDERABLE avalanche danger exist in wind loaded areas on NW-N-NE-E aspects, 35 degrees and steeper. Below treeline, areas of MODERATE danger exist in wind affected areas on all aspects, 35 degrees and steeper.

Brandon Schwartz - Avalanche Forecaster, Tahoe National Forest

Weather Observations from along the Sierra Crest between 8200 ft and 8800 ft:

0600 temperature:	15 to 18 deg. F.
Max. temperature in the last 24 hours:	21 to 23 deg. F.
Average wind direction during the last 24 hours:	East shifting to southwest
Average wind speed during the last 24 hours:	38 mph
Maximum wind gust in the last 24 hours:	65 mph
New snowfall in the last 24 hours:	3 to 11 inches
Total snow depth:	82 to 111 inches

Two-Day Mountain Weather Forecast - Produced in partnership with the Reno NWS

For 7000-8000 ft:
	Friday:	Friday Night:	Saturday:
Weather:	Cloudy skies with snow showers in the morning. Numerous snow showers in the afternoon.	Mostly cloudy skies with a chance of snow showers.	Partly cloudy skies with a slight chance of snow showers.
Temperatures:	20 to 27 deg. F.	7 to 14 deg. F.	21 to 28 deg. F.
Wind direction:	SW	SW	W
Wind speed:	15 to 25 mph with gusts to 40 mph. Winds decreasing to 10 to 15 mph with gusts to 25 mph in the afternoon.	10 to 15 mph with gusts to 25 mph in the evening.	Up to 10 mph in the morning becoming light.
Expected snowfall:	2 to 4 in.	0 to trace in.	0 to trace in.
For 8000-9000 ft:
	Friday:	Friday Night:	Saturday:
Weather:	Cloudy skies with snow showers in the morning. Numerous snow showers in the afternoon.	Mostly cloudy skies with a chance of snow showers.	Mostly cloudy skies in the morning, becoming partly cloudy. Slight chance of snow showers.
Temperatures:	19 to 25 deg. F.	5 to 12 deg. F.	18 to 25 deg. F.
Wind direction:	SW	W	NW
Wind speed:	20 to 30 mph with gusts to 50 mph. Gusts decreasing to 35 mph in the afternoon.	10 to 20 mph with gusts to 40 mph. Gusts decreasing to 30 mph after midnight.	10 to 15 mph with gusts to 25 mph in the morning.
Expected snowfall:	2 to 4 in.	0 to trace in.	0 to trace in.