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 Friday, January 26, 2007 at 3:42 pm

The bottom line: Avalanche danger is LOW for all elevations and aspects. Human triggered avalanches are unlikely but not impossible near treeline on NW-N-NE aspects, 35 degrees and steeper.

Our next fund raiser is another ski day on February 4th at Homewood. Tickets are on sale now at Snowbomb.com. 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. Your support is what makes the Sierra Avalanche Center possible. For more details on the current financial situation please click here.

A weak low pressure system is moving near the coast of California and will increase cloud cover over the forecast area tonight and Saturday. A chance of very light snowfall exists, mainly Saturday night. This is dependent on the exact track of the system and how close it actually comes to the Sierra. Air temperatures are expected to cool slightly again tomorrow. Ridgetop winds are expected to remain light through Saturday.

Observations made today show the first snowpit data indicating that enough gradual weakening of the snowpack has occurred to introduce the remote possibility of shallow human triggered avalanches. Near treeline areas on NW-N-NE aspects that hold a relatively stiff surface slab created by strong E and NE wind events over the past few weeks are suspect. This wind slab sits on top of a very eroded crust and a layer of near surface facets. Shear failure at this interface in response to human triggers is not outside the realm of possibility. Layer bonding tests now show very moderate shear failure at the interface of faceted snow and the upper most crust layer located within the top 1 foot of the snowpack on northerly aspects. At this time, we do not have enough snowpack data to warrant a Moderate danger rating. Backcountry travelers are advised to take normal travel precautions, exposing only one person at a time when traveling in avalanche terrain. Snow on shaded northerly aspects is remaining cold despite above freezing air temperatures. Daily melt-freeze conditions continue to occur on the vast majority of southerly aspects, especially below 9,000'.

The bottom line: Avalanche danger is LOW for all elevations and aspects. Human triggered avalanches are unlikely but not impossible near treeline on NW-N-NE aspects, 35 degrees and steeper.

The next scheduled update to this advisory will occur around noon tomorrow.

Brandon Schwartz, Avalanche Forecaster

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Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet): 30 deg. F
Max. temperature at Sierra Crest past 24 hours: 40 deg. F
Average wind direction at Sierra Crest past 24 hours: southwesterly
Average wind speed at Sierra Crest past 24 hours: 14 mph
Maximum wind gust at Sierra Crest past 24 hours: 36 mph
New snow fall at 8,200 feet past 24 hours: 0 inches
Total snow depth at 8,200 feet: 34 inches

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Mountain Weather Forecast For Saturday:
Partly cloudy skies
Temperature forecast for 8,000 to 9,000 feet: 29 - 34 deg. F
Ridgetop winds forecast for the Sierra Crest: southeasterly 10 - 15 mph
Snowfall expected in the next 24 hours: 0 inches

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2 Day Mountain Weather Forecast:
7000 to 8000 Feet
Tonight, becoming partly cloudy with lows 17 to 27 degrees, F. Southwest winds 10 to 20 mph shifting to southeast after midnight. Saturday, partly cloudy skies with daytime highs around 36 degrees F. Southeast winds at 10 to 15 mph are expected.

Above 8000 Feet
Tonight, becoming partly cloudy with lows 20 to 26 degrees, F. South winds 10 to 15 mph. Saturday, partly cloudy skies with daytime highs around 33 degrees F. Southeast winds at 10 to 15 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:
	Friday:	Friday Night:	Saturday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.
For 8000-9000 ft:
	Friday:	Friday Night:	Saturday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.