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 break in the weather will occur today before the next major storm system arrives late Tuesday. Expect periods of sunshine and broken cloud cover during the day with light winds at all elevations. Yesterday's snow shower activity added an additional trace to 2 inches. This brings new snow amounts for the past 48 hours up to 3 to 10 inches, with the Sierra Crest heavily favored. Southwest ridgetop winds that were moderate to strong in speed yesterday shifted to west last night. Winds are decreasing in speed this morning. Air temperatures at 8,500' are in the upper teens to low 20s this morning. Around 7 to 10 degrees of daytime warming is expected.

Observations:

Yesterday on Silver Peak (Pole Creek area) strong ridgetop winds continued to transport snow (photo, pit profile, more info). Wind loading that occurred in lee areas was noted as further down slope than the typical avalanche start zones. Winds slabs existed in all open areas above and below treeline. No obvious signs of instability such as cracking or collapsing were observed. Snowpit data obtained at 8,020' on a N aspect near treeline revealed an easy shear within the new snow and a moderate shear on near crust facets that had formed below the Dec 19 rain crust. Fracture propagation test results indicated that propagation was unlikely on either weak layer in this area.

Primary avalanche concern: Wind Slabs

The significant wind transport of snow and subsequent wind loading that occurred from mid day Saturday through last night has created widespread wind slabs. In most areas these slabs are stable, but lingering pockets of instability likely exist. Southwest to west winds have deposited snow in lee areas, often well below ridgelines. Areas of complex terrain on N-NE-E-SE aspects are the most suspect. Evidence of snowpack instability will not be obvious today. Careful and diligent slope evaluation is required to detect linger pockets of instability. Any avalanche activity that occurs today is expected to be human triggered and occur within the recent new snow. Snowpack failure at the Dec 19 rain crust is unlikely but not impossible.

The bottom line:

Near and above treeline, avalanche danger is LOW with isolated pockets of MODERATE danger lingering on N-NE-E-SE aspects, 35 degrees and steeper. Below treeline, avalanche danger is LOW with isolated pockets of MODERATE danger lingering on N-NE-E 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:	17 to 23 deg. F.
Max. temperature in the last 24 hours:	20 to 25 deg. F.
Average wind direction during the last 24 hours:	Southwest shifting to west
Average wind speed during the last 24 hours:	48 mph
Maximum wind gust in the last 24 hours:	82 mph
New snowfall in the last 24 hours:	Trace to 2 inches
Total snow depth:	63 to 93 inches

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

For 7000-8000 ft:
	Monday:	Monday Night:	Tuesday:
Weather:	Partly cloudy skies in the morning, becoming mostly cloudy.	Cloudy skies with a slight chance of snow showers after midnight.	Cloudy skies with a slight chance of snow showers in the morning. A chance of snow in the afternoon.
Temperatures:	28 to 35 deg. F.	21 to 28 deg. F.	28 to 35 deg. F.
Wind direction:	W	W shifting to SW	SW
Wind speed:	Up to 10 mph.	Up to 10 mph.	10 to 15 mph with gusts to 25 mph in the afternoon.
Expected snowfall:	O in.	Trace in.	Up to 2 in.
For 8000-9000 ft:
	Monday:	Monday Night:	Tuesday:
Weather:	Partly cloudy skies in the morning, becoming mostly cloudy.	Cloudy skies with a slight chance of snow showers after midnight.	Cloudy skies with a slight chance of snow showers in the morning. Snow likely in the afternoon.
Temperatures:	24 to 31 deg. F.	21 to 28 deg. F.	24 to 31 deg. F.
Wind direction:	W	W	W
Wind speed:	Around 10 mph.	Around 10 mph. Gusts to 25 mph after midnight.	10 to 20 mph with gusts to 30 mph. Winds increasing to 20 to 30 mph with gusts to 50 mph in the afternoon.
Expected snowfall:	O in.	Trace in.	Up to 2 in.