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 snow showers that started yesterday afternoon should continue today. These snow showers should increase during the day bringing another 2-5 inches of snow to the central Sierra. A brief period of strong southwesterly winds occurred late yesterday as this low pressure system started to impact the forecast area. These winds started to decrease to more moderate speeds overnight. They should shift more to the south today before shifting to the northeast and increasing overnight as the system moves east of the forecast area.

2 to 3 inches of new snow fell on the western side of the forecast area overnight. Only about 1 inch accumulated east of Lake Tahoe. Observations on Rubicon Peak and in the Mt. Rose area prior to the onset of snowfall yesterday continued to show a mix of frozen melt/freeze crusts on the southerly aspects, unconsolidated surface snow and near surface facets on the northerly aspects sheltered from the wind and sun, and crusts from wind and sun on exposed northerly aspects. Observers also reported that the storm began with bursts of graupel (the snow equivalent of ball bearings) in both of these areas with almost 1/4 inch of these small, rimed, spheres accumulating in the Mt. Rose area by late yesterday. 

Today the primary avalanche concern will be new wind slabs. These wind slabs should start out relatively small this morning due to the small amount of new snow received overnight. As more snow accumulates and more wind loading occurs today, these wind slabs will grow. Near and above treeline on the leeward NW-N-NE aspects heavier wind loading may create some pockets of  wind slabs large enough to cause dangerous avalanche conditions for backcountry travelers. These pockets of larger wind slabs may also form on W and E aspects due to cross loading if the winds shift all the way to the south today. The new wind slabs will be sitting on the snow surfaces mentioned above all of which could easily serve as weak layers or sliding surfaces depending on how well the new snow bonds to them. Human triggering of these wind slabs on slopes steeper than 35 degrees should become possible by this afternoon and evening. Avalanches resulting from these new wind slabs should only involve the new snow. Use blowing snow, drifts, cornices, ripples, and other signs of wind transport to help determine which slopes have received the most wind loading and use extra caution around these slopes.

The bottom line:

This morning the avalanche danger is LOW for all elevations and aspects. Near and above treeline some pockets of MODERATE danger may develop on W-NW-N-NE-E aspects steeper than 35 degrees by this afternoon. Use safe travel habits and good route finding when traveling 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:	23 deg. F.
Max. temperature in the last 24 hours:	28-31 deg. F.
Average wind direction during the last 24 hours:	Southwest
Average wind speed during the last 24 hours:	30-35 mph
Maximum wind gust in the last 24 hours:	64 mph
New snowfall in the last 24 hours:	2-3 inches
Total snow depth:	67 inches

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

For 7000-8000 ft:
	Friday:	Friday Night:	Saturday:
Weather:	Scattered snow showers in the morning becoming more widespread and intense this afternoon	Snow showers	Snow showers continuing in the morning but decreasing in the afternoon
Temperatures:	25-32 deg. F.	17-24 deg. F.	26-33 deg. F.
Wind direction:	South	Northeast	Northeast
Wind speed:	10-15 mph with gusts to 25 mph	10-15 mph with gusts to 25 mph	10-20 mph with gusts to 30 mph
Expected snowfall:	2-4 in.	1-3 in.	up to 2 in.
For 8000-9000 ft:
	Friday:	Friday Night:	Saturday:
Weather:	Scattered snow showers in the morning becoming more widespread and intense this afternoon	Snow showers	Snow showers continuing in the morning but decreasing in the afternoon
Temperatures:	21-28 deg. F.	18-24 deg. F.	21-28 deg. F.
Wind direction:	South	Northeast	Northeast
Wind speed:	15-20 mph with gusts to 40 mph	10-15 mph with gusts to 25 mph	20-30 mph with gusts to 40 mph in the morning decreasing to 10-20 mph with gusts to 30 mph in the afternoon
Expected snowfall:	2-5 in.	2-5 in.	up to 2 in.