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.

Remote sensors above 8000' reported overnight lows between 37 and 40 degrees F (several degrees above freezing). Below 7000' the sensors reported overnight lows in the low 30's indicating a slight temperature inversion. The high pressure over the forecast area will keep temperatures warm with daytime highs forecasted to reach into the upper 40's to mid 50's at all elevations again today. The winds should remain light but shift to the southwest. By tomorrow, some cloud cover could develop over the area due to a low-pressure system approaching the Pacific Northwest.

Observations:

Yesterday morning a hard, supportable, thick, frozen crust existed on the snow surface on the E-SE-S-SW-W aspects due to a solid refreeze the night before. By 10:30 am on Rose Knob Peak, enough melting had occurred for 2-4 inches of soft "corn" snow to form on the sun-exposed E-SE-S aspects between 9700' and 7400'. In the more shaded areas the snow surface remained frozen all the way down to 7400' until at least 11 am. Cold, dry snow still remained on the northerly aspects above 9000'. On the more exposed northerly slopes, a mix of wind scoured surfaces and wind packed snow existed on the snow surface. Softer snow may still exist on high-elevation sheltered northerly aspects. Similar snow surface conditions have been observed in other areas over the past few days (more info).

Avalanche concerns: Warming instability

Even though air temperatures remained above freezing last night, clear skies will have allowed the snowpack to lose enough heat for a decent overnight refreeze (radiational cooling). This refreeze will not be as strong as yesterday's. The snow surface should melt and soften more quickly this morning as the sun hits the snow and the air temperatures start to climb. Enough melting and warming could occur for wet-snow instabilities to form today on the sun-exposed E-SE-S-SW-W aspects. Very isolated areas of wet-snow instability are possible on NW-N-NE aspects below 7,500'. These wet-snow instabilities will most likely manifest as loose snow avalanches, roller-balls, and pinwheels involving the top few inches of wet surface snow. Sinking into wet snow above your boot tops indicates that enough melting has occurred for wet-snow instabilities to pose a threat and that the time has come to move on to a less melted more supportable aspect.

The bottom line:

This morning, LOW avalanche danger exists for all elevations and aspects. Pockets of MODERATE avalanche danger will quickly develop at all elevations on E-SE-S-SW-W aspects 37 degrees and steeper in response to daytime warming.

Andy Anderson - Avalanche Forecaster, Tahoe National Forest

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

0600 temperature:	38 deg. F.
Max. temperature in the last 24 hours:	50-54 deg. F.
Average wind direction during the last 24 hours:	Northeast shifting to the southwest yesterday afternoon/evening
Average wind speed during the last 24 hours:	Northeast: 15 mph | Southwest: 10 mph
Maximum wind gust in the last 24 hours:	35 mph
New snowfall in the last 24 hours:	O inches
Total snow depth:	85-121 inches

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

For 7000-8000 ft:
	Saturday:	Saturday Night:	Sunday:
Weather:	Sunny	Clear	Partly cloudy
Temperatures:	49-56 deg. F.	23-30 deg. F.	43-50 deg. F.
Wind direction:	Southwest	Southwest	Southwest
Wind speed:	10 mph	10-15 mph	10-15 mph with gusts to 25 mph increasing to 10-20 mph with gusts to 30 mph
Expected snowfall:	O in.	O in.	O in.
For 8000-9000 ft:
	Saturday:	Saturday Night:	Sunday:
Weather:	Sunny	Clear	Partly cloudy
Temperatures:	49-55 deg. F.	22-29 deg. F.	42-48 deg. F.
Wind direction:	Southwest	Southwest	Southwest
Wind speed:	10-15 mph with gusts to 25 mph	15-25 mph decreasing to 10-15 mph with gusts to 35 mph after midnight	10-15 mph with gusts to 30 mph increasing to 20-30 mph with gusts to 45 mph in the afternoon
Expected snowfall:	O in.	O in.	O in.