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 moving across the forecast area over the next 24 hours should bring 2-3 inches of new snow to the Sierra. The forecast calls for only one inch during the day today and another one to two inches tonight.  Light snow has started to fall as this system approaches the area. The winds have also shifted to the southwest and increased ahead of this low. By tomorrow the low pressure should have moved east of the region and the snow showers should end. As another high pressure builds over the forecast area tomorrow, temperatures should start to warm up. Click here for a graphic explaining today's small storm.

Observations:

Observations in Negro Canyon yesterday continued to indicate a strong and stable snowpack with stability tests like ski and snowmobile cuts on steep slopes, hand pits, and layer bonding tests all showing stable results. A mix of wind crusts and firm wind scoured surfaces existed on the higher elevation, more exposed NW-N-NE-E aspects near ridgelines. On the W-SW-S-SE aspects, sometimes breakable and sometimes supportable sun crusts, and melt-freeze crusts formed the snow surface up to 7800 ft. On the more protected and lower elevation (below 7500 ft) N-NE-E aspects, 4-8 inches of cold, soft snow remained widespread on the surface. This surface layer of soft snow even existed on open lower elevation northerly slopes (video).

Avalanche Concerns: Wind Slabs

The new snow that falls today will combine with the southwest winds to form small wind slabs on the N-NE-E aspects near and above treeline. These wind slabs should remain very small and shallow since the forecast only calls for one inch of new snow today. Even though these slabs may break in response to a person's weight, dangerous avalanche activity should remain unlikely today due to the small size and shallowness of any new wind slabs. Continue to use caution and evaluate slopes carefully before committing to them. Small and very isolated pockets of where more wind loading has created slightly larger slabs are not impossible. If more snow falls than forecasted, these wind slabs will become larger and more widespread and the avalanche danger will increase.

The bottom line:

The avalanche danger should remain LOW for all elevations and aspects today. If more snow falls than forecasted, the avalanche danger will increase. Continue to use normal caution when travelling in the backcountry.

Andy Anderson - Avalanche Forecaster, Tahoe National Forest

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

0600 temperature:	17-22 deg. F.
Max. temperature in the last 24 hours:	30-32 deg. F.
Average wind direction during the last 24 hours:	East until 5pm yesterday then Southwest
Average wind speed during the last 24 hours:	East: 5-10 mph Southwest: 25-30 mph
Maximum wind gust in the last 24 hours:	52 mph
New snowfall in the last 24 hours:	trace inches
Total snow depth:	68-98 inches

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

For 7000-8000 ft:
	Tuesday:	Tuesday Night:	Wednesday:
Weather:	Snow showers this morning becoming more widespread during the day.	Snow with snow showers decreasing after midnight.	Mostly cloudy with a slight chance of snow in the morning.
Temperatures:	25-32 deg. F.	20-29 deg. F.	34-41 deg. F.
Wind direction:	Southwest	Southwest	Southwest
Wind speed:	10-15 mph with gusts to 35 mph	10-15 mph	around 10 mph
Expected snowfall:	up to 1 in.	1-2 in.	O in.
For 8000-9000 ft:
	Tuesday:	Tuesday Night:	Wednesday:
Weather:	Snow showers this morning becoming more widespread during the day.	Snow with snow showers decreasing after midnight.	Mostly cloudy with a slight chance of snow in the morning.
Temperatures:	23-30 deg. F.	19-25 deg. F.	34-41 deg. F.
Wind direction:	Southwest	Southwest	Southwest
Wind speed:	15-20 mph with gusts to 30 mph increasing to 25-35 mph with gusts to 50 mph	15-25 mph with gusts to 40 mph	15-25 mph with gusts to 45 mph
Expected snowfall:	1 in.	1-2 in.	O in.