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.

After dropping to around 7200 ft. yesterday morning, snow levels climbed back up to around 8200 ft. for the rest of the day. The storm dropped another .1-.4 inches of rain below 8200 ft. and another 1-3 inches of wet, heavy snow above 8200 ft yesterday. One sensor reported 1.2 inches of rain in the northern half of the forecast area. This additional accumulation brings storm snow totals above 8200 ft to two to four inches. This system started to dissipate last night, and skies began to clear as a small high pressure ridge started to push its way into the forecast area. The clouds should continue to decrease this morning, and the weather should dry out as this ridge establishes itself over the region. This high pressure should also push daytime highs back up into the mid to upper 40's above 7000 ft today. Later today and this evening the clouds should increase again ahead of another weak low pressure system. As this system starts to arrive tomorrow a chance of showers should develop over the area, and the southwest winds should start to increase.

Observations:

By yesterday evening 8-16 inches of wet snow existed on the snow surface on Donner Peak and Andesite Ridge. In some areas a person could sink up to his knee in wet, rain-soaked snow if he stepped out of his skis. Above 8000 ft on Andesite Ridge, one to two inches of wet new snow existed. Some roller balls and small wet sluffs involving this new snow occurred on steep N-NE facing slopes due to ski cuts in this area (more info). On Donner Peak on a SE facing aspect around 7200 ft, a small, skier-triggered, wet, loose point release occurred on a 36 degree slope. On nearby E-NE facing slopes the rain had caused a large natural cornice failure and some natural rock fall. When the large cornice pieces and the rocks hit the steep slopes below, they entrained some of the wet surface snow but did not cause any larger wet snow instabilities (photos and more info). 

Primary Avalanche Concern: Warming Instabilities

Clearing skies last night and overnight lows close to freezing should have allowed a moderate refreeze to occur last night. This refreeze should not have penetrated deep enough to affect all of the wet snow that existed in the snowpack yesterday. Expect to find wet snow below last night's melt-freeze crust today. Sun and warmer air temperatures today should provide enough warming to melt most of the melt-freeze crust that formed last night. This melting should create enough wet snow for some wet snow instabilities to form. These wet snow instabilities should remain limited to wet point release avalanches and roller balls. Some wet slab avalanches will also become possible in areas where last night's melt-freeze crust melts completely today. Most of the wet snow slides should remain too small to bury a person; however, larger ones are not impossible. Even the smaller wet snow slides could entrain enough snow to knock a person off course and into a terrain trap where serious consequences could result. Sun-exposed E-SE-S-SW-W aspects and any aspects that have significant new snow on them will have the best potential for producing wet snow avalanches today.

The bottom line:

Areas of MODERATE avalanche danger should form on E-SE-S-SW-W aspects at all elevations today due to daytime warming. Small pockets of MODERATE danger may also form on NW-N-NE aspects near and above treeline north of Hwy 50 where new snow exists as the day warms up. 

Andy Anderson - Avalanche Forecaster, Tahoe National Forest

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

0600 temperature:	29-32 deg. F.
Max. temperature in the last 24 hours:	31-36 deg. F.
Average wind direction during the last 24 hours:	Southwest
Average wind speed during the last 24 hours:	25-35 mph
Maximum wind gust in the last 24 hours:	50 mph
New snowfall in the last 24 hours:	Below 8200 ft Rain: .1-.4 inches - above 8200 ft Snow: 1-3 inches
Total snow depth:	92-158 inches

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

For 7000-8000 ft:
	Tuesday:	Tuesday Night:	Wednesday:
Weather:	Partly cloudy	Mostly cloudy	Cloudy with a slight chance of showers in the morning then a chance of snow in the afternoon.
Temperatures:	45-49 deg. F.	22-26 deg. F.	42-48 deg. F.
Wind direction:	Southwest	Southwest	Southwest
Wind speed:	10-15 mph with gusts to 35 mph	10-15 mph with gusts to 35 mph	10-15 mph increasing to 15-25 mph with gusts to 55 mph
Expected snowfall:	O in.	O in.	trace in.
For 8000-9000 ft:
	Tuesday:	Tuesday Night:	Wednesday:
Weather:	Partly cloudy	Mostly cloudy	Cloudy with a slight chance of showers in the morning then a chance of snow in the afternoon.
Temperatures:	38-44 deg. F.	20-27 deg. F.	36-42 deg. F.
Wind direction:	Southwest	Southwest	Southwest
Wind speed:	15-25 mph with gusts to 35 mph	15-25 mph with gusts to 35 mph	20-35 mph increasing to 30-40 mph with gusts to 65 mph
Expected snowfall:	O in.	O in.	trace in.