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 storm system that has affected the forecast area for the past few days will slowly exit to the east today. Storm totals are now running around 7 to 16 inches with the greatest accumulations in the southern portion of the forecast area. Most areas along the Sierra Crest pickup up another 5 inches of new snow last night with 7 to 10 inches of new snow in the Carson Range. Upslope flow will keep snow showers going today with another 1 to 4 inches of new snow expected. Air temperatures above 8,000' this morning are in the mid 20s, about 5 to 10 degrees warmer than 24 hours ago. Ridgetop winds shifted to the northeast overnight and are forecast to remain light to moderate in speed today. For tomorrow, sunny skies and above freezing air temperatures at all elevations are expected

Observations:

Yesterday, two intentionally human triggered slab avalanches occurred in response to slope cuts above Crater Lake on Red Lake Peak (Carson Pass area). The avalanches occurred in above treeline terrain around 9,000' on NE aspect 35 to 40 slopes. Crown heights measured 3 to 12 inches, 50 ft wide and the avalanches ran about 500 ft down slope. The failure layer was noted within the storm snow just above the melt freeze crust at the old/new snow interface. This was likely the same lower density layer of new snow near the bottom of the storm snow that has been noted around the forecast area over the past two days. On Hidden Peak (West Shore Tahoe area), unstable slabs of the same upside-down storm snow were observed in the most wind affected areas near treeline on NE-E aspects at 9,000' (photos, pit profile). In less wind affected areas, skier triggered sluffs occurred in very steep areas where no slab existed. On Powerhouse Peak (Luther Pass area), observations showed minimal to no slab formation. The same upside-down low density layer weaknesses within the new snow was observed in near treeline N aspect terrain along the summit ridge at 9,300'. Ski cuts produced minimal results. Some very small and localized loose snow failures occurred on steep convex rolls below treeline (photo, more info).

Avalanche Concerns: Storm snow

Avalanche concerns for today continue to focus on instability occurring within the storm snow. Natural avalanche activity is not expected today, but widespread human triggering of avalanches remains possible in recently wind loaded areas near and above treeline. Slab avalanche instability is most likely to occur on NW-N-NE-E aspects, but will likely extend to recently wind loaded areas on other aspects as well. Ridgetop winds have shifted from the SW and W to the NE overnight with some degree of redistribution of storm snow expected. In general, slab depth is expected to be 8 inches to 2 feet deep with larger slabs possible in the far southern portion of the forecast area. The upside-down portion of lower density new snow near the bottom of the storm snow layer is expected to remain the main weak layer. Below treeline, small isolated human triggered avalanches are possible on steep convex terrain features on all aspects. Of note, Extended Column Tests performed yesterday on Hidden Peak on the edge of a test slope slab failure produced false stable results, which tend to occur at a rate of 6% to 10% (pit profile).

The bottom line:

Near and above treeline, avalanche danger is MODERATE in recently wind loaded areas on all aspects on slopes 35 degrees and steeper. Below treeline, pockets of MODERATE danger exist on all aspects in open areas on slopes 35 degrees and steeper.

Brandon Schwartz - Avalanche Forecaster, Tahoe National Forest

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

0600 temperature:	24 to 28 deg. F.
Max. temperature in the last 24 hours:	29 to 30 deg. F.
Average wind direction during the last 24 hours:	West shifting to northeast.
Average wind speed during the last 24 hours:	20 mph
Maximum wind gust in the last 24 hours:	40 mph
New snowfall in the last 24 hours:	5 to 10 inches
Total snow depth:	98 to 147 inches

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

For 7000-8000 ft:
	Thursday:	Thursday Night:	Friday:
Weather:	Mostly cloudy to cloudy skies with numerous snow showers, becoming scattered.	Mostly cloudy skies with a slight chance of snow showers in the evening. Partly cloudy skies after midnight.	Sunny skies.
Temperatures:	29 to 36 deg. F.	20 to 27 deg. F.	47 to 53 deg. F.
Wind direction:	NE	NE	NE
Wind speed:	Around 10 mph with gusts to 30 mph.	10 to 15 mph.	Around 10 mph.
Expected snowfall:	Up to 3 in.	0 to trace in.	O in.
For 8000-9000 ft:
	Thursday:	Thursday Night:	Friday:
Weather:	Mostly cloudy to cloudy skies with numerous snow showers, becoming scattered.	Mostly cloudy skies with a slight chance of snow showers in the evening. Partly cloudy skies after midnight.	Sunny skies.
Temperatures:	25 to 32 deg. F.	21 to 28 deg. F.	38 to 46 deg. F.
Wind direction:	NE	NE	NE
Wind speed:	10 to 20 mph with gusts to 35 mph.	10 to 20 mph with gusts to 30 mph. Gusts increasing to 50 mph after midnight.	10 to 15 mph with gusts to 30 mph.
Expected snowfall:	2 to 4 in.	0 to trace in.	O in.