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.

Some scattered showers started to occur in the northern part of the forecast area last night. Some sensors along the Sierra Crest north of Echo Summit indicated up to 1 inch of new snow above 8200 ft. and about .5 inches of rain below 8200 ft. Rain and snow showers should continue today due to a weak system moving through the area. The forecast calls for snow levels to remain between 7500 and 8500 ft. 1-2 inches of new snow could fall above 8000 ft. Below 8000 ft. most of the precip should fall as rain. The southwest winds have also increased and should continue to gain strength as this system moves through the area. By tonight the showers and winds should start to decrease and continue to do so into tomorrow. Cold air following this system should push temperatures down into the low to upper 30's for this afternoon and tomorrow.

Recent Observations:

Yesterday around mid-day on Incline Lake Peak (video, photo, more info), a strong frozen 6-8 inch melt-freeze crust existed below 1-2 inches of soft wet surface snow on the E-SE-S-SW aspects. Below this crust another layer of wet loose snow 6-10 inches thick existed (video). Ski cuts on steep test slopes did result in some small roller ball activity, but the strong supportable melt-freeze crust prevented deeper loose wet snow instabilities from occurring (photo). On the the northerly aspects 2-4 inches of wet sticky snow existed above a frozen melt-freeze crust. Below this more crusts alternated with layers of consolidated cold dry snow. 

Avalanche Problem #1: Loose Wet Avalanches

Warm temperatures and rain on the snowpack below 8500 ft. today should allow more wet loose snow instabilities to form on all aspects. The rain may melt the refrozen layer that formed over the last few nights. Human triggered wet loose avalanches consisting of point releases, large roller balls and pinwheels, and wet snow sluffs should continue today. Some of these could still become large and entrain some of the deeper wet snow that still exists below the surface. Above 8500 ft. colder temperatures should prevent wet snow instabilities from forming.

Avalanche Problem #2: Wet Slabs

Wet slab avalanche activity remains unlikely today due to a lack weak layers within the snowpack and the fact that well established drainage channels exist to prevent water from pooling in the snowpack . Still, variability in storm snow amounts and deep wet snow mean that a very isolated wet slab avalanche is not impossible today below the rain line.

The bottom line:

Both above and below treeline, MODERATE danger will form on all aspects below 8500 ft. on slopes 35 degrees and steeper due to rain on snow. Human triggered loose wet avalanches remain possible today.

Andy Anderson - Avalanche Forecaster, Tahoe National Forest

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

0600 temperature:	34-39 deg. F.
Max. temperature in the last 24 hours:	46-54 deg. F.
Average wind direction during the last 24 hours:	Southwest
Average wind speed during the last 24 hours:	15-30 mph
Maximum wind gust in the last 24 hours:	51 mph
New snowfall in the last 24 hours:	0-1 inches
Total snow depth:	45-82 inches

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

For 7000-8000 ft:
	Thursday:	Thursday Night:	Friday:
Weather:	Rain showers below 7500 ft. A mix of rain and snow above 7500 ft	Rain and snow showers decreasing in the evening and becoming scattered after midnight	Mostly cloudy with a slight chance of showers
Temperatures:	41-48 deg F. falling to 34-40 deg. F.	27-32 deg. F.	35-45 deg. F.
Wind direction:	Southwest	Southwest	Southwest
Wind speed:	10-20 mph with gusts to 30 mph increasing to 20-35 mph with gusts to 50 mph in the afternoon	20-35 mph with gusts to 50 mph decreasing to 10-20 mph with gusts to 30 mph after midnight	10-15 mph with gusts to 25 mph
Expected snowfall:	Rain: up to .25 in.	up to 1 in.	O in.
For 8000-9000 ft:
	Thursday:	Thursday Night:	Friday:
Weather:	A mix of rain and snow below 8500 ft. Snow above 8500 ft.	Snow showers decreasing in the evening and becoming scattered after midnight	Mostly cloudy with a slight chance of snow showers
Temperatures:	34-43 deg F. falling to 27-34 deg. F.	22-27 deg. F.	24-35 deg. F.
Wind direction:	Southwest	Southwest	Southwest
Wind speed:	30-45 mph increasing to 45-55 mph with gusts to 70 mph in the afternoon	40-55 mph with gusts to 70 mph decreasing to 20-35 mph with gusts to 50 mph after midnight	20-30 mph with gusts to 45 mph
Expected snowfall:	1-2 in.	up to 1 in.	O in.