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 Saturday, January 20, 2007 at 2:16 pm

Our current financial situation is still in jeopardy. (for details click here) We still do not have enough money to finish out this season. We need your help to make our second fundraiser this Sunday at Kirkwood a success. By purchasing a $40 SAC ski day lift ticket online for Sunday at Snowbomb.com, you will get to ride the lifts at Kirkwood for 40% off of their normal rate. The entire purchase price of $40 goes directly to supporting the Sierra Avalanche Center. This event is much more than just a day of cheap resort skiing. We will be there all day to meet you and answer your questions. Lots of other folks who are traditionally in the backcountry will also be there trading stories and making turns together. On top of the fun, we will have some great raffle prizes to give away. If you can't make it but would still like to help out, please make a tax deductible donation directly to us via Paypal or by sending a check to our address listed above, c/o the Truckee Ranger Station. Thank you for your support.

One very week weather disturbance is moving through the forecast area today and another is expected to pass through tonight. These systems are expected to produce some mid to high level clouds and moderate northerly to easterly ridgetop winds, but no precipitation. Air temperatures at the 8,000' level are expected to rise a little above freezing in the afternoon for each of the next several days.

Cold snowpack temperatures continue on northerly aspects at all elevations as well as on all aspects above 8,700'. A temperature gradient of 1 to 3 degrees C. per 10 cm of height continues to exist within the snowpack. Observed gradients are stronger at the upper elevations. The existing temperature gradients are strong enough to create sufficient vapor pressure to continue the faceting of snow crystals within the snowpack. The rate of faceting continues to slow in response to gradual warming of air and snowpack temperatures, but the process has not yet stopped. Moderate to hard force shears continue to emerge on faceted layers in response to layer bonding tests. Overall, the snowpack remains stable at this time, but it continues to gradually loose strength day to day. The snowpack on E-S-W aspects below 8,700' is recovering nicely after the cold air temperatures of last week. Diurnal melt-freeze of surface snow is occurring on southerly aspects below 8,500'.

Snow surface conditions remain variable by aspect and elevation. There are two options for the best riding conditions, given the current weather and snowpack. Below treeline, some pockets of shallow, unconsolidated snow linger on northwesterly aspects that are well protected from east winds. Above treeline, snow covered south aspects in the 7,500' to 8,500' elevation range are receiving sufficient sun to soften and provide fun turns around mid day. Above treeline on all aspects, stable hard slab conditions exist. Near and below treeline is a mix of melt-freeze crust, stable hard slab, and unconsolidated snow depending on aspect. There are beacon basins located at the base of Squaw Valley, Heavenly, and Kirkwood, if you have yet to practice you rescue skills this season.

Avalanche danger is LOW for all elevations and aspects.

The next scheduled update to this advisory will occur tomorrow evening.

Brandon Schwartz, Avalanche Forecaster

--------------------------------------------------------------------------------

Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet): 24 deg. F
Max. temperature at Sierra Crest past 24 hours: 35 deg. F
Average wind direction at Sierra Crest past 24 hours: northeasterly
Average wind speed at Sierra Crest past 24 hours: 20 mph
Maximum wind gust at Sierra Crest past 24 hours: 39 mph
New snow fall at 8,200 feet past 24 hours: 0 inches
Total snow depth at 8,200 feet: 35 inches

--------------------------------------------------------------------------------
Mountain Weather Forecast For Today:
Partly cloudy skies
Temperature forecast for 8,000 to 9,000 feet: 33 - 38 deg. F
Ridgetop winds forecast for the Sierra Crest: northeasterly 10 - 20 mph with gusts to 25 mph.
Snowfall expected in the next 24 hours: 0 inches

--------------------------------------------------------------------------------
2 Day Mountain Weather Forecast:
7000 to 8000 Feet
Tonight, partly cloudy skies with lows 12 to 18 degrees, F. North winds 10 to 15 mph. Sunday, sunny skies with daytime highs around 34 degrees F. Northeast winds 10 to 20 mph. Overnight, partly cloudy skies with lows around 15 degrees F. East winds at 15 to 25 mph, gusting to 40 mph. Monday will be sunny with daytime highs around 36 degrees F. East winds at 20 to 30 mph, gusting to 45 mph are expected.

Above 8000 Feet
Tonight, partly cloudy skies with lows around 16 degrees F. North winds 25 to 35 mph, gusting to 70 mph after midnight. Sunday, sunny skies with daytime highs around 33 degrees F. Northeast winds 20 to 30 mph, gusting to 65 mph. Overnight, partly cloudy skies with lows around 15 degrees F. East winds 30 to 45 mph, gusting to 70 mph. Monday will be sunny with daytime highs around 35 degrees F. East winds at 25 to 35 mph, gusting to 60 mph are expected.

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:
	Saturday:	Saturday Night:	Sunday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.
For 8000-9000 ft:
	Saturday:	Saturday Night:	Sunday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.