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.

A low pressure system offshore this morning will pass to the south of the forecast area today. Cloudy skies and snowfall are expected for today. New snow amounts for the past 30 hours are running 7 to 10 inches across the forecast area. An additional 5 to 12 inches of new snow is forecast for today. The greatest accumulations associated with this storm system are expected to occur south of Hwy 50. Ridgetop winds shifted from southwest to southeast overnight and have decreased to light in speed this morning. Southeast winds are forecast to increase to moderate in speed as the day progresses. An additional 2 to 5 inches of snowfall and moderate speed east winds are expected tonight.

Observations:

Observations made yesterday on Jake's Peak (West Shore Tahoe area) revealed instability within the storm snow, just above the old/new snow interface. The weak layer was noted as a slight density change of higher density new snow over lower density new snow. In near treeline and below treeline areas, the storm snow lacked sufficient cohesion to create slab avalanches. Widespread skier triggered loose snow avalanches large enough to carry a person down slope were observed on N-NE-E aspects steeper than 35 degrees (photos, video, more info).

Squaw Valley Professional Ski Patrol reported that avalanche reduction work via ski cutting produced widespread but small slab avalanches yesterday morning. These avalanches occurred in wind loaded and cross loaded near and above treeline terrain on N-NE-E aspects. These slabs failed within the new snow, just above the old/new snow interface creating crowns 4 to 6 inches deep. Since these avalanches were occurring within the new snow, similar conditions likely existed in the backcountry immediately outside the ski area boundary.

Avalanche Concern #1: Storm snow slabs

Additional snowfall of 5 to 12 inches today combined with moderate speed SE winds are expected to increase the size and distribution of storm snow slabs that already exist. The shift from yesterday's SW winds to today's SE winds will put wind loading and cross loading in more than the usual locations. Slab avalanche activity is expected to expand from yesterday's instability on N-NE-E aspects to include W-NW aspects today. Human triggered avalanches are likely today and natural avalanches are possible with snowpack failure expected to occur within the storm snow.

Avalanche Concern #2: Loose snow avalanches

In wind protected upper elevation areas and in most lower elevation areas, human triggered loose snow avalanches are expected to continue today. This avalanche type will be possible in steep areas on all aspects. Loose snow avalanches may entrain significant amounts of snow today. The potential for loose snow avalanches to carry a person into areas of high consequence secondary terrain hazards such as cliffs, trees, rock bands, and terrain traps exists today.

The bottom line:

Near and above treeline avalanche danger will rise to CONSIDERABLE today on W-NW-N-NE-E aspects, 35 degrees and steeper. Below treeline MODERATE danger exists on all aspects on slopes 35 degrees and steeper. The areas of greatest avalanche danger today are expected to occur south of Highway 50.

Brandon Schwartz - Avalanche Forecaster, Tahoe National Forest

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

0600 temperature:	21 to 24 deg. F.
Max. temperature in the last 24 hours:	27 to 29 deg. F.
Average wind direction during the last 24 hours:	Southwest shifting to southeast
Average wind speed during the last 24 hours:	Prior to 6 pm 40 mph, after 6pm 15 mph
Maximum wind gust in the last 24 hours:	68 mph
New snowfall in the last 24 hours:	7 to 10 inches
Total snow depth:	79 to 106 inches

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

For 7000-8000 ft:
	Sunday:	Sunday Night:	Monday:
Weather:	Cloudy skies with snow.	Cloudy skies with snow.	Cloudy skies in the morning, becoming mostly cloudy. A chance of snow.
Temperatures:	18 to 25 deg. F.	8 to 15 deg. F.	16 to 23 deg. F.
Wind direction:	SE	E	E
Wind speed:	10 to 15 mph with gusts to 30 mph in the morning.	10 to 15 mph with gusts to 25 mph after midnight.	10 to 15 mph with gusts to 25 mph.
Expected snowfall:	5 to 10 in.	2 to 4 in.	0 to trace in.
For 8000-9000 ft:
	Sunday:	Sunday Night:	Monday:
Weather:	Cloudy skies with snow.	Cloudy skies with snow.	Cloudy skies in the morning, becoming mostly cloudy. A chance of snow.
Temperatures:	15 to 22 deg. F.	7 to 14 deg. F.	13 to 20 deg. F.
Wind direction:	SE	E	E
Wind speed:	20 to 30 mph with gusts to 50 mph.	20 to 30 mph with gusts to 45 mph.	15 to 25 mph with gusts to 45 mph. Winds decreasing to 10 to 15 mph with gusts to 25 mph in the afternoon.
Expected snowfall:	7 to 12 in.	3 to 5 in.	0 to trace in.