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.

Due to a small high pressure ridge over the forecast area, today's weather should include partly sunny skies, light to moderate northwest winds, and daytime highs in the low to mid 30's. By tonight more cloud cover should arrive, and the winds should shift to the southwest and increase as a winter storm approaches the area. This storm should bring colder temperatures and 6-12 inches of snow to the region above 7000 ft. The snowfall should begin during the night tonight and continue through tomorrow with the heaviest snowfall occurring Monday morning. At the onset of this storm, the forecast calls for snow levels around 5000 ft. Snow levels should fall to around 3000-4000 ft during the day on Monday. Click here for a weather map showing more information about the storm.

Recent Observations:

Yesterday, observations from Meiss Ridge (photos, snowpit, more info), Castle Peak (photos, snowpit, more info), and Tamarack Peak (photos, snowpit, more info) all showed data consistent with other recent observations across the forecast area. A mix of crusts and shallow soft snow existed on the surface of the northerly aspects. Some of the crusts remained supportive, and some of them have become very thin and easily breakable. Thin layers of weak sugary snow known as facets remain just below the surface layers on these aspects. On the sun exposed southerly aspects, melt-freeze conditions predominate. On all aspects recent snowpits have shown strong snow exists in the lower portion of the snowpack. On Castle Peak and on Meiss Ridge, partly cloudy skies with periods of sunshine did allow minor melting and softening to occur on a few of the sun-exposed southerly aspects. In the Mt Rose area. more clouds and cooler temperatures kept the snow surface frozen on the southerly aspects.

Today's Avalanche Concerns:

Some melting and softening may occur on the sun-exposed southerly aspects today. This melting should not cause any significant wet snow instabilities to form due to cooler daytime highs, some cloud cover, light northwest winds, and a prolonged period of melt-freeze cycles that have allowed the current snowpack to establish drainage channels preventing water from collecting in a single layer. Even though a possible weak layer does exist on the northerly aspects in the form of the near surface facets mentioned above, as of now, no slab layers reside on top of this weak layer. Today's weather will not form any new slab layers on top of the snowpack. However, the snow and wind that accompany the winter storm forecasted to impact the area from late tonight through Monday could easily build new slabs on top of the current snowpack. As these new slabs form on top of the existing weak layers, the avalanche danger will increase. Avalanche activity should become possible again by tomorrow. 

The bottom line:

Avalanche danger remains LOW for all elevations and aspects. Use normal caution when traveling in the backcountry. As more snow and wind impact the forecast area late tonight through tomorrow, the avalanche danger will increase.

Andy Anderson - Avalanche Forecaster, Tahoe National Forest

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

0600 temperature:	19-23 deg. F.
Max. temperature in the last 24 hours:	28-38 deg. F.
Average wind direction during the last 24 hours:	Southwest shifting to northwest and northeast
Average wind speed during the last 24 hours:	10 mph
Maximum wind gust in the last 24 hours:	23 mph
New snowfall in the last 24 hours:	trace to 2 inches
Total snow depth:	18-33 inches

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

For 7000-8000 ft:
	Sunday:	Sunday Night:	Monday:
Weather:	Partly cloudy this morning becoming mostly cloudy in the afternoon	Cloudy with a slight chance of snow in the evening. Snow becoming widespread after midnight	Snow
Temperatures:	32-39 deg. F.	20-25 deg. F.	22-29 deg. F.
Wind direction:	Northwest	Southwest	Southwest shifting to the west in the afternoon
Wind speed:	10-15 mph with gusts between 25 and 30 mph	15-25 mph with gusts to 40 mph	20-25 mph with gusts to 40 mph decreasing to 10-15 mph with gusts to 25 mph in the afternoon
Expected snowfall:	O in.	2-4 in.	4-8 in.
For 8000-9000 ft:
	Sunday:	Sunday Night:	Monday:
Weather:	Partly cloudy this morning becoming mostly cloudy in the afternoon	Cloudy with a slight chance of snow in the evening. Snow becoming widespread after midnight	Snow
Temperatures:	30-36 deg. F.	16-21 deg. F.	18-23 deg. F.
Wind direction:	Northwest	Southwest	Southwest shifting to the west in the afternoon
Wind speed:	15-25 mph with gusts to 40 mph	25-35 mph with gusts to 40 mph increasing to 55 mph after midnight	30-35 mph with gusts to 50 mph decreasing to 15-20 mph with gusts to 30 mph in the afternoon
Expected snowfall:	O in.	2-4 in.	4-8 in.