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 since Friday is starting to taper off. Cold front passage occurred yesterday afternoon/evening decreasing air temperatures and snow level across the region. New snowfall amounts in the last 24 hours at 8,500' are 7 to 16 inches, bringing storm totals up to 29 to 49 inches with 8+ inches of rain water equivalent. Air temperatures this morning at 8,500' are in the upper teens with around 5 degrees of daytime warming expected. Ridgetop winds remain out of the southwest this morning and have decreased from gale force to moderate in speed. Winds are expected to further decrease in speed this afternoon. Snowfall will be much less organized today as a short wave passes through the area. This will produce snow showers with new snow accumulations highly varied by location. An additional 3 to 6 inches of new snow is expected to accumulate over most of the forecast area today with up to 12 inches forecast for the far southern portion of the forecast area (Alpine County).

Observations:

Yesterday on Silver Peak (Pole Creek area), evidence of a large recent natural avalanche was observed. The avalanche is believed to have occurred around 10:30am Sunday morning. The start zone was a convex wind loaded E aspect bowl above treeline at 8,350'. The crown was approximately 600' wide, 3' deep and the avalanche ran 1000 vertical feet. This avalanche was full clean out of the avalanche path and ran the full distance of the path (photos, more info). Below treeline at 7,500', ski cutting a convex test slope produced a small slab avalanche involving the top 6 to 8 inches of rain wetted new snow (photo, more info). Test pits were dug on this slope and a second location nearby in an area that was noted previously to have surface hoar up to 4 cm at the base of the storm snow. Both pits revealed no evidence of ongoing instability with this already collapsed surface hoar layer. Snow level had risen to around 7,700' by mid day in this area.

Avalanche Concern #1: Wind Slabs

The combination of new snow and wind over the past 24 hours is expected to have further enhanced existing slab formation in wind loaded areas. Natural slab avalanches remain possible today while human triggered slab avalanches remain likely near and above treeline on steep NW-N-NE-E-SE aspects. Most of the avalanche activity that occurs today is expected to involve new snow from the past 24 hours. However, large and destructive avalanches with snowpack failure deep within the recent storm snow remain possible.

Avalanche Concern #2: Loose snow avalanches

Cooling air temperatures since yesterday afternoon have placed lower density new snow on top of higher density new snow. In wind protected areas below treeline, this will limit slab formation and allow most snowpack failure to occur as loose snow avalanches (sluffs) involving the upper portion of the recent storm snow. Secondary terrain hazards such as cliffs, terrain traps, trees, and exposed rocks will drastically increase the consequences of becoming caught in a loose snow avalanche.

The bottom line:

Near and above treeline, avalanche danger is CONSIDERABLE on NW-N-NE-E-SE aspects, 35 degrees and steeper. Below treeline, avalanche danger is MODERATE in open areas on all aspects, 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:	16 to 20 deg. F.
Max. temperature in the last 24 hours:	29 to 34 deg. F.
Average wind direction during the last 24 hours:	Southwest
Average wind speed during the last 24 hours:	65 mph
Maximum wind gust in the last 24 hours:	155 mph
New snowfall in the last 24 hours:	7 to 16 inches
Total snow depth:	73 to 102 inches

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

For 7000-8000 ft:
	Monday:	Monday Night:	Tuesday:
Weather:	Cloudy skies with snow.	Cloudy skies with snow showers likely.	Mostly cloudy skies with scattered snow showers.
Temperatures:	24 to 29 deg. F.	17 to 22 deg. F.	25 to 30 deg. F.
Wind direction:	SW	SW	S
Wind speed:	15 to 30 mph with gusts to 45 mph. Winds decreasing to 10 to 20 mph with gusts to 35 mph in the afternoon.	10 to 20 mph with gusts to 30 mph.	10 to 20 mph with gusts to 35 mph.
Expected snowfall:	3 to 6 in. with locally up to 12 in.	Up to 2 in.	Up to 1 in.
For 8000-9000 ft:
	Monday:	Monday Night:	Tuesday:
Weather:	Cloudy skies with snow.	Cloudy skies with snow showers likely.	Mostly cloudy skies with scattered snow showers.
Temperatures:	19 to 24 deg. F.	15 to 20 deg. F.	21 to 26 deg. F.
Wind direction:	SW	SW	S
Wind speed:	20 to 30 mph with gusts to 45 mph. Winds decreasing to 15 to 25 mph with gusts to 35 mph in the afternoon.	10 to 20 mph increasing to 15 to 25 mph after midnight. Gusts up to 35 mph.	20 to 30 mph with gusts to 60 mph.
Expected snowfall:	3 to 6 in. with locally up to 12 in.	Up to 2 in.	Up to 1 in.