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.

High pressure will remain in place over the forecast area until the end of the week before a pattern change is expected. Light winds and above freezing air temperatures are expected again today at the upper elevations. An air temperature inversion is in place this morning with the coldest air below around 7,000' in mountain locations.

Snowpack observations continue to reveal pockets of terrain that hold an unstable snowpack. Persistent weak instability continues to exist above 8,600' on NW-N-NE aspects that receive some degree of wind protection from NE winds. This is mainly near treeline and below treeline areas where the snowpack consists of recent new or wind affected snow on top of the October 19 facet layer. This snow sits on top of the early Oct ice mass which covers the ground in these areas. Yesterday, observations from the south side of Carson Pass revealed whumpfing and shooting cracks (photo) near treeline at 8,600' on a N aspect, 30 degree slope. The Oct 19 facet layer sitting on top of the early Oct ice mass was identified as the buried weak layer in this area. Very similar conditions were noted in similar terrain on Monday near the Mount Rose Hwy Summit (photo).

A second snowpack instability was discovered yesterday on Silver Peak (Pole Creek area) near treeline at 8,100' on a NE aspect, 28 degree slope. In this case the Oct 19 facet layer was identified sitting on the ground with a one foot slab of November's, slightly wind affected snow sitting on top of it (photo). Similar terrain characteristics of northerly aspect, near treeline or below treeline, and at least somewhat NE wind protected, overlap with other locations where instabilities involving the Oct 19 facet layer are noted. Stability tests produced very repeatable clean shears (Q1) and collapse of the facet layer under moderate to hard force. Fracture propagation tests indicated that fracture propagation was likely on this layer given a similar trigger. No obvious signs of instability such as whumpfing or shooting cracks were observed in this area.

Today, pockets of instability remain in areas where the Oct 19 facet layer is present. Many of these areas are the areas where the deepest sections of the overall very shallow snowpack and the best snow surface conditions for recreation exist. Feeling with poles or feet will easily detect the presence of the early Oct ice mass. Quick hand pits will identify the presence or absence of the soft and sugary Oct 19 facet layer on top of the ice mass or at ground level. Where these two buried layers exist, slopes steeper than 32 degrees are best avoided. In other areas where the Oct 19 facet layer does not exist, rocks and down trees that lurk under the thin snow cover are the greatest hazard to backcountry travelers.

The bottom line:

Pockets of MODERATE avalanche danger exist above 8,000' in near treeline and below treeline areas on slopes 32 degrees and steeper. For all other areas, avalanche danger is LOW.

Brandon Schwartz - Avalanche Forecaster, Tahoe National Forest

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

0600 temperature:	34 deg. F.
Max. temperature in the last 24 hours:	44 deg. F.
Average wind direction during the last 24 hours:	NE
Average wind speed during the last 24 hours:	9 mph
Maximum wind gust in the last 24 hours:	18 mph
New snowfall in the last 24 hours:	O inches
Total snow depth:	8 to 25 inches

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

For 7000-8000 ft:
	Wednesday:	Wednesday Night:	Thursday:
Weather:	Sunny skies.	Clear skies.	Sunny skies.
Temperatures:	40 to 45 deg. F.	19 to 29 deg. F.	41 to 46 deg. F.
Wind direction:	N	E	E
Wind speed:	Light winds	Up to 10 mph.	Up to 10 mph.
Expected snowfall:	O in.	O in.	O in.
For 8000-9000 ft:
	Wednesday:	Wednesday Night:	Thursday:
Weather:	Sunny skies.	Clear skies.	Sunny skies.
Temperatures:	34 to 42 deg. F.	23 to 30 deg. F.	36 to 43 deg. F.
Wind direction:	N	NE	NE
Wind speed:	Up to 10 mph.	10 to 15 mph with gusts to 25 mph.	10 to 15 mph with gusts to 25 mph.
Expected snowfall:	O in.	O in.	O in.