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.

One more day of snowfall is in store for the forecast area before a break in the weather occurs tomorrow and Friday. A period of steady snowfall is expected from 7am to 11am this morning with lighter snow showers for the rest of the day. Light snow fell across the region overnight depositing 1 to 3 inches of new snow. An additional 1 to 4 inches of new snow is expected to fall this morning. Air temperatures at 8,500' are on a warming trend with most locations in the upper 20s. A few degrees of cooling are expected to occur today. Ridgetop winds shifted from southwest to south yesterday morning and increased to moderate to strong in speed for a few hours last night. Winds have decreased to light to moderate in speed this morning and are forecast to shift to the southwest.

Observations:

Observations made yesterday in the Mount Rose, Donner Summit, and Echo Summit areas all showed rapid stabilization of the recent storm snow. Density inversions that produced widespread avalanche activity on Monday no longer produced failures in any type of formal or informal fracture propagation tests. (more info, photos, pit profiles). The recent storm snow now appears well bonded to the rain crust and higher density snow layers in the upper portion of the snowpack. Cornices remain weak and easily collapse under the weight of a person.

Primary avalanche concern: Wind Slabs

Remote sensors indicate that ridgetop winds increased in speed overnight. This is expected to have transported snow and caused wind loading on NW-N-NE-E aspects. Warming air temperatures overnight are expected to have further enhanced any slab formation. A period of steady snowfall this morning will add size to the small slabs that already exist. Avalanche activity that occurs today is expected to be human triggered and involved the top 1 foot of the snowpack. Snowpack failure occurring deeper in the recent storm snow is unlikely but not impossible, especially in areas of complex or extreme terrain.

 

The bottom line:

Near and above treeline, avalanche danger is MODERATE on NW-N-NE-E aspects, 35 degrees and steeper. Below treeline, avalanche danger is LOW with pockets of MODERATE danger in open areas on NW-N-NE-E 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:	25 to 30 deg. F.
Max. temperature in the last 24 hours:	25 to 30 deg. F.
Average wind direction during the last 24 hours:	South
Average wind speed during the last 24 hours:	33 mph
Maximum wind gust in the last 24 hours:	72 mph
New snowfall in the last 24 hours:	1 to 3 inches
Total snow depth:	68 to 94 inches

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

For 7000-8000 ft:
	Wednesday:	Wednesday Night:	Thursday:
Weather:	Cloudy skies with snow in the morning. Numerous snow showers in the afternoon.	Mostly cloudy skies with scattered snow showers in the evening. Isolated snow showers after midnight.	Partly to mostly cloudy skies.
Temperatures:	27 to 32 deg. F.	17 to 22 deg. F.	31 to 34 deg. F.
Wind direction:	S shifting to SW	SW	SW
Wind speed:	Up to 10 mph.	Up to 10 mph.	Up to 10 mph.
Expected snowfall:	1 to 4 in.	0 to trace in.	O in.
For 8000-9000 ft:
	Wednesday:	Wednesday Night:	Thursday:
Weather:	Cloudy skies with snow in the morning. Numerous snow showers in the afternoon.	Mostly cloudy skies with scattered snow showers in the evening. Isolated snow showers after midnight.	Partly to mostly cloudy skies.
Temperatures:	Around 25 deg. F.	Around 20 deg. F.	31 to 34 deg. F.
Wind direction:	S shifting to SW	SW	SW
Wind speed:	10 to 20 mph with gusts to 35 mph.	10 to 20 mph with gusts to 30 mph.	10 to 20 mph with gusts to 30 mph. Gusts increasing to 50 mph late in the day.
Expected snowfall:	1 to 4 in.	0 to trace in.	O in.