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.

Colder air is moving into the forecast area this morning behind the departing weather system. Lingering showers are expected today with some sun breaks occurring. Precipitation amounts from the past 36 hours vary greatly across the forecast area. Storm totals range from 3 to 12 inches of new snow above 7,000' from up to 1.4 inches of rain water equivalent. The southern half of the forecast area received the greatest amount of new snow and experienced the lowest snow levels. This morning, remote sensors above 8,000' are reporting air temperatures in the low to upper 20s. Maximum daytime air temperatures are forecast to reach the mid 20s to upper 30s today for areas above 7,000'. Ridgetop winds have shifted slightly from the southwest to west this morning. Light to moderate speed west winds are forecast to continue through tonight. Light northeast winds are forecast for tomorrow morning.

Recent Observations:

Observations made yesterday on Andesite Peak (Donner Summit area) revealed significantly less new snow existed in that area than was reported from other locations of similar elevation around the forecast area. Rain on snow at 8,200' prior to snowfall had created a 3.5 inch thick wet layer just below 2.5 inches of new snow. The deeper portions of the snowpack that had experienced free water percolation from melt in the days prior to this storm cycle were well drained of free water and in a state of refreezing. The new snow amounts in this area of 2.5 inches were insufficient for significant slab formation to occur. Winds were light with little to no evidence of previous wind loading. Human triggered roller ball activity was limited to small roller balls initiating off of ski turns (video, photo, pit profile, more info).

Avalanche problem #1: Wind Slabs

A second round of significant snowfall occurred in some portions of the forecast area last night. This second round of snowfall was associated with more wind than the period of snowfall that occurred yesterday morning. New wind slab formation with slabs up to 1.5 feet thick are expected in wind loaded areas near and above treeline, mainly on N-NE-E aspects. In areas that received more snowfall these slabs will be present. In areas that received little to no new snow, these wind slabs will be absent.

Avalanche Problem #2: Storm Slabs

Storm slabs that formed from new snow deposition over the past 36 hours are highly variable in thickness, in direct correlation to variations in snowfall amounts around the forecast area. In areas that received the high end of new snow amounts, storm slabs to 1 foot thick exist in wind protected areas. In locations that received only a few inches of new snow, these slabs are generally too thin to present a significant hazard to backcountry travelers.

Avalanche Problem #3: Loose Wet Avalanches

As air temperatures have cooled, loose wet avalanches have become less likely. A lingering concern remains below 7,000' where recent rain on snow has kept the snowpack warmer. In areas where the snow surface has not refrozen and become supportable, isolated human triggered loose wet avalanches remain possible.

The bottom line:

Above 7,000', avalanche danger is MODERATE on all aspects on slopes 35 degrees and steeper due to a mix of storms slabs and wind slabs. Below 7,000', avalanche danger is LOW with pockets of MODERATE danger on all aspects on slopes 35 degrees and steeper due to the possibility of human triggered loose wet avalanches.

Brandon Schwartz - Avalanche Forecaster, Tahoe National Forest

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

0600 temperature:	25 to 29 deg. F.
Max. temperature in the last 24 hours:	30 to 38 deg. F.
Average wind direction during the last 24 hours:	Southwest
Average wind speed during the last 24 hours:	25 mph
Maximum wind gust in the last 24 hours:	43 mph
New snowfall in the last 24 hours:	1 to 6 inches
Total snow depth:	51 to 83 inches

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

For 7000-8000 ft:
	Monday:	Monday Night:	Tuesday:
Weather:	Mostly cloudy skies with scattered showers.	Partly cloudy skies with a slight chance of showers in the evening.	Partly cloudy skies.
Temperatures:	32 to 40 deg. F.	27 to 32 deg. F.	45 to 52 deg. F.
Wind direction:	W	W	NE
Wind speed:	5 to 15 mph.	5 to 15 mph becoming light.	Light winds
Expected snowfall:	Less than 1 in.	0 to trace in.	O in.
For 8000-9000 ft:
	Monday:	Monday Night:	Tuesday:
Weather:	Mostly cloudy skies with scattered snow showers.	Partly cloudy skies with a slight chance of snow showers in the evening.	Partly cloudy skies.
Temperatures:	24 to 32 deg. F.	24 to 32 deg. F.	35 to 45 deg. F.
Wind direction:	W	W	NE
Wind speed:	15 to 20 mph with gusts to 30 mph.	15 to 20 mph with gusts to 30 mph in the evening, becoming light.	10 to 15 mph in the morning, becoming light.
Expected snowfall:	1 in.	0 to trace in.	O in.