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.

The first in a series of significant weather systems to impact the forecast area this week will move onshore today. Snow level is forecast for 5,500' to 6,000' today with a period of moderate to heavy snowfall in the afternoon or evening hours. New snow accumulations of 11 to 26 inches are expected above 7,000' over the next 36 hours. Ridgetop winds shifted from south to southwest yesterday afternoon and will remain out of the southwest through Monday. Wind speeds will continue to increase today with gusts up to 80 mph forecast for this afternoon. Expect daytime highs above 7,000' in the low to mid 30s.

Observations:

Observations made yesterday at Crater Lake on Red Lake Peak (Carson Pass area) above treeline at 8,830' on a N aspect 35 degree slope indicated that a weak layer of slightly faceted crystals had formed on top of the crust that was buried on January 11. Fracture propagation tests yielded inconsistent results, but fracture propagation was shown as possible along this layer (pit profile). Observations made in Horse Canyon (near Bear Valley Ski Area) near treeline at 8,110' on a N aspect 30 degree slope showed that the snowpack contained no significant weak layers and is in very good condition to handle new snow loading (pit profile).

Avalanche concerns:

Once significant snowfall begins later today, small unstable slabs are expected to begin to form in wind loaded areas. This will occur mainly near and above treeline on N-NE-E aspects. As additional snowfall occurs during the overnight hours, these slabs will become larger and more widespread. Any areas of instability that form late today are expected to involve only the new snow. As more significant snowfall accumulates overnight, failure deeper in the snowpack may occur in areas where small faceted crystals have been observed on top of the Jan 11 crust that exists around 1 foot deep in the snowpack.

The bottom line:

This morning, avalanche danger is LOW for all elevations and aspects. Following the onset of snowfall, pockets of MODERATE danger are expected to develop near and above treeline in wind loaded areas on N-NE-E aspects, 37 degrees and steeper in the late afternoon or evening hours. Avalanche danger is expected to continue to rise overnight into Monday.

Brandon Schwartz - Avalanche Forecaster, Tahoe National Forest

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

0600 temperature:	24 to 28 deg. F.
Max. temperature in the last 24 hours:	35 to 40 deg. F.
Average wind direction during the last 24 hours:	South shifting to Southwest
Average wind speed during the last 24 hours:	33 mph
Maximum wind gust in the last 24 hours:	60 mph
New snowfall in the last 24 hours:	O inches
Total snow depth:	45 to 68 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 a slight chance of snow in the morning, then snow in the afternoon.	Cloudy skies with snow.	Cloudy skies with snow.
Temperatures:	30 to 37 deg. F.	22 to 29 deg. F.	27 to 34 deg. F.
Wind direction:	SW	S	S
Wind speed:	15 to 20 mph with gusts to 35 mph.	20 to 30 mph with gusts to 35 mph. Gusts increasing to 45 mph after midnight.	20 to 35 mph with gusts to 55 mph.
Expected snowfall:	1 to 3 in.	3 to 7 in.	7 to 11 in.
For 8000-9000 ft:
	Sunday:	Sunday Night:	Monday:
Weather:	Cloudy skies with a slight chance of snow in the morning, then snow in the afternoon.	Cloudy skies with snow.	Cloudy skies with snow.
Temperatures:	29 to 35 deg. F.	19 to 26 deg. F.	27 to 33 deg. F.
Wind direction:	SW	S shifting to SW after midnight.	SW
Wind speed:	30 to 45 mph with gusts to 65 mph. Gusts increasing to 80 mph in the afternoon.	30 to 45 mph increasing to 40 to 50 with gusts to 80 mph after midnight.	45 to 65 mph with gusts to 90 mph. Gusts increasing to 100 mph in the afternoon.
Expected snowfall:	2 to 3 in.	5 to 9 in.	10 to 14 in.