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.

An inversion exists across the forecast area today with temperatures in the mid 20's below 7000'. The Sierra Valleys hold the coldest pockets of air with temperatures in the teens. A small cold front should begin to replace the high-pressure ridge over the next 24 hours. As this front moves into the area, winds should start to increase. These winds should help break the inversion today. By this weekend temperatures should cool off in response to this cold front. The forecast calls for a small chance of light snow with this system. A series of more-active, wetter weather should follow this system next week.

Yesterday, no one reported any human-triggered whumfing, snowpack collapse, or shooting cracks for the first time since mid Nov. Moderate to hard force still caused the Oct. 19th facet layer to break during layer bonding tests in the Mt. Rose area yesterday. These tests also still showed that when these facets break the fracture can propagate through the snowpack along this layer. Observers have reported similar test results in other areas where this layer exists. Above 8600' these facets often sit on an ice layer. Between 8000' and 8600', they often sit on the ground. The snowpack remains weak where this layer exists. Unfortunately, where the weakest snowpack exists corresponds to the the areas where the best recreation exists. With more snow forecasted for next week this persistent weak layer will continue to cause avalanche problems.

Today human-triggered avalanche activity will remain possible on slopes where the Oct. 19 facet layer exists with a slab sitting on top of it. Observers have reported this layer combination on the NW-N-NE aspects near and below treeline above 8000' all week. These areas will continue to pose the greatest avalanche threat to backcountry travelers. Initiating a fracture in this facet layer will be easiest near trigger-points where a thinner slab exists above the facets or where this layer is weakest. Quick hand pits or probing with a ski pole can identify whether the soft, sugary Oct 19 facet layer exists in the snowpack. In areas where this layer exists, slopes steeper than 32 degrees hold the potential for human-triggered avalanches.

Use extra caution in the backcountry today.  A persistent weak layer with variable strength and distribution provides a complex avalanche hazard. Along with the avalanche hazard, the early season snowpack just barely covers the myriad of rocks, dirt, stumps, shrubbery, and other toy-damaging, knee-breaking obstacles.

The bottom line:

LOW avalanche danger exists in most areas. However, pockets of MODERATE avalanche danger remain on NW-N-NE aspects above 8,000' in near-treeline and below-treeline areas on slopes 32 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:	35 deg. F.
Max. temperature in the last 24 hours:	40 deg. F.
Average wind direction during the last 24 hours:	East shifting to the West Southwest
Average wind speed during the last 24 hours:	25 mph
Maximum wind gust in the last 24 hours:	53 mph
New snowfall in the last 24 hours:	O inches
Total snow depth:	8-20 inches

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

For 7000-8000 ft:
	Friday:	Friday Night:	Saturday:
Weather:	Partly cloudy	Partly cloudy	Mostly cloudy with a slight chance of snow showers
Temperatures:	37-44 deg. F.	18-25 deg. F.	27-34 deg. F.
Wind direction:	Southwest	Southwest	West
Wind speed:	10-15 mph	10-15 mph	10-20 mph with gusts to 30 mph
Expected snowfall:	O in.	O in.	trace in.
For 8000-9000 ft:
	Friday:	Friday Night:	Saturday:
Weather:	Partly cloudy	Partly cloudy	Mostly cloudy with a slight chance of snow showers
Temperatures:	35-42 deg. F.	18-25 deg. F.	27-33 deg. F.
Wind direction:	Southwest	Southwest	West
Wind speed:	10-15 mph with gusts to 30 mph	10-20 mph with gusts to 40 mph	20-30 mph with gusts to 55 mph
Expected snowfall:	O in.	O in.	trace in.