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.

This advisory was posted on Tuesday, January 2, 2007 at 6:45 am

The air temperature inversion will strengthen today, decreasing temperatures in the valleys and slightly increasing temperatures at the upper elevations. Yesterday's strong east wind event is weakening this morning. Ridgetop winds are expected to become light during the day today and shift to westerly over the next 24 hours, as the next storm system approaches the forecast area. The next opportunity for significant snowfall is expected to begin late Wednesday.

The snowpack throughout the forecast area is stable at this time. A mix a snow surface conditions exists with areas of melt-freeze crust and/or hard, wind scoured snow surfaces found in near and above treeline areas on all aspects. Below treeline, unconsolidated snow lingers in well protected areas on northerly aspects. The layers deeper within the snowpack have all bonded well since the last storm. With the approaching storm system, the lingering area of concern is basal layer depth hoar that exists on NW-N-NE-E aspects above 8,500'. The snowpack above this sugar like snow layer is very strong and able to keep the snowpack from failing at this time. This basal depth hoar layer needs continued evaluation as the potential for heavy snowfall and subsequent heavy loading exists with the approaching storm. The deep Sierra snowpack that has been present during January of recent years does not exist so far this winter. Our current snowpack is very shallow and has a greater potential for ground level failure during the next storm than the snowpack that backcountry travelers have become familiar with in recent years.

At this time, avalanche danger is LOW for all elevations and aspects. Currently, one of the most significant hazards to backcountry travelers is the presence of hard snow surfaces above treeline. The potential for a long sliding fall exists. Take note of the consequences of sudden deceleration against rocks or trees.

Brandon Schwartz, Avalanche Forecaster

Today's Central Sierra Weather Observations:

0500 temperature at Sierra Crest (8,700 feet): 30 deg. F
Max. temperature at Sierra Crest past 24 hours: 30 deg. F
Average wind direction at Sierra Crest past 24 hours: easterly
Average wind speed at Sierra Crest past 24 hours: 53 mph
Maximum wind gust at Sierra Crest past 24 hours: 101 mph
New snow fall at 8,200 feet past 24 hours: 0 inches
Total snow depth at 8,200 feet: 33 inches

Mountain Weather Forecast For Today:

Mostly cloudy skies.
Temperature forecast for 8,000 to 9,000 feet: 44 - 49 deg. F
Ridgetop winds forecast for the Sierra Crest: northeasterly 15 - 30 mph, G 35 mph
Snowfall expected in the next 24 hours: 0 inches

2 Day Mountain Weather Forecast:

7000 to 8000 Feet
For today, becoming mostly cloudy with daytime highs around 48 degrees F. Overnight lows 27 to 33 degrees F under mostly cloudy skies. Westerly winds at 15 to 20 mph. Wednesday will be mostly cloudy with daytime highs around 46 degrees F. Southwesterly winds at 30 to 45 mph are expected.

Above 8000 Feet
For today, mostly cloudy with daytime highs 44 to 49 degrees F. Overnight lows around 32 degrees F. Westerly winds at 20 to 30 mph, gusting to 50 mph after midnight. Wednesday will be mostly cloudy with daytime highs around 43 degrees F. Winds out of the west at 45 to 60 mph, gusting to 90 mph. Gusts are expected to increase to 105 mph in the afternoon.

The bottom line:

Andy Anderson - Avalanche Forecaster, Tahoe National Forest

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

0600 temperature:	deg. F.
Max. temperature in the last 24 hours:	deg. F.
Average wind direction during the last 24 hours:
Average wind speed during the last 24 hours:	mph
Maximum wind gust in the last 24 hours:	mph
New snowfall in the last 24 hours:	O inches
Total snow depth:	inches

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

For 7000-8000 ft:
	Tuesday:	Tuesday Night:	Wednesday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.
For 8000-9000 ft:
	Tuesday:	Tuesday Night:	Wednesday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.