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 over the Pacific Northwest should push more clouds and light snow to the forecast area today. The forecast calls for up to 2 inches above 7000'. Snow showers should taper off this afternoon as a high pressure ridge begins to move into the region. The low pressure system will keep the southwest winds blowing strong though tonight. By tomorrow the winds and cloud cover should start to decrease, while the temperatures start to increase.

Observations:

Backcountry skiers triggered another small avalanche yesterday on a NE facing slope on Mt. Judah near treeline (photo). This small slide was about 1.5 ft deep and 30 ft. wide. The second skier on the slope triggered the slide and was able to ski out to the side of it. The avalanche continued down the slope for another 75 ft. past him. Observations on Andesite Ridge (Donner Summit area), Incline Lake Peak (Mt. Rose area), and Tamarack Peak (Mt. Rose area) showed that the strong southwest  winds continued to transport snow onto the leeward aspects through the day yesterday. Near and above treeline on the wind-loaded slopes, some skier-triggered cracking occurred in the recently-formed wind-slabs in all three locations. These wind-slabs were limited to areas near ridgelines and only extended a short distance down-slope in all three locations. Below treeline observations and snowpit data indicated mostly stable snow in all three locations.

Avalanche concern #1:

Even though the new snow has consolidated and bonded to the old-snow surfaces in many areas, isolated pockets of human-triggerable wind-slabs will continue to exist today near and above treeline on NW-N-NE-E-SE aspects steeper than 35 degrees. These wind-slabs have grown over the last 36 hours and could be 1-3 ft deep in these areas.  Large tender cornices remain perched above many of these wind-slabs. Avalanches will be harder to trigger today than yesterday. However, avalanches large enough to bury or injure a person remain possible.

Avalanche concern #2:

Below treeline, pockets of continued instability remain on the colder and shadier NW-N-NE aspects. In these areas pockets of terrain exist where the new snow has not fully consolidated, and it sits on top of a thin layer of weak, sugary crystals about 1ft. deep in the snowpack. These crystals exist just below a thin rain-crust that formed on Dec. 21. Probing with a ski pole or digging a quick hand pit can reveal the presence or absence of this layer.

Avalanche concern #3:

Deep slab instability involving the Oct 19 facet layer near the base of the snowpack is unlikely but not impossible in a few isolated areas below treeline on sheltered NW-N-NE aspects above 7,700'. Very strong snow in the middle and upper portions of the snowpack has kept this layer from failing in areas where it remains weak. Human triggering of this weak layer remains an unlikely event.

The bottom line:

Near and above treeline, pockets of MODERATE avalanche danger exist on NW-N-NE-E-SE aspects, 35 degrees and steeper. Below treeline, pockets of MODERATE danger exist in open areas on NW-N-NE aspects, 37 degrees and steeper.

Andy Anderson - Avalanche Forecaster, Tahoe National Forest

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

0600 temperature:	29 deg. F.
Max. temperature in the last 24 hours:	32 deg. F.
Average wind direction during the last 24 hours:	Southwest
Average wind speed during the last 24 hours:	45 mph
Maximum wind gust in the last 24 hours:	79 mph
New snowfall in the last 24 hours:	O inches
Total snow depth:	37-63 inches

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

For 7000-8000 ft:
	Friday:	Friday Night:	Saturday:
Weather:	Cloudy with snow showers in the morning. Snow showers should become scattered and start to taper off after 2 pm.	Cloudy with a few scattered snow showers	Mostly cloudy
Temperatures:	33-37 deg. F.	22-28 deg. F.	36-41 deg. F.
Wind direction:	Southwest	West	Southwest
Wind speed:	15-20 mph with gusts to 40 mph	10-20 mph with gusts to 35 mph decreasing to 10-15 mph with gusts to 25 mph after midnight	10-15 mph
Expected snowfall:	up to 2 in.	trace to .5 in.	O in.
For 8000-9000 ft:
	Friday:	Friday Night:	Saturday:
Weather:	Cloudy with snow showers in the morning. Snow showers should become scattered and start to taper off after 2 pm.	Cloudy with a few scattered snow showers	Mostly cloudy
Temperatures:	28-33 deg. F.	20-25 deg. F.	34-39 deg. F.
Wind direction:	Southwest	Southwest	West
Wind speed:	30-35 mph with gusts to 70 mph	30-35 mph with gusts to 70 mph	15-25 mph with gusts to 45 mph decreasing to 10-15 mph with gusts to 25 mph in the afternoon
Expected snowfall:	up to 2 in.	up to 1 in.	O in.