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 Monday, January 29, 2007 at 8:00 pm

The bottom line: Avalanche danger is LOW for all elevations and aspects. Remember that low danger does not mean no danger. Even though human triggered avalanches are unlikely, there are a few small, isolated areas of instability on NW-N-NE aspects, 35 degrees and steeper. Continue to practice safe travel techniques like traveling one at a time through avalanche terrain and be especially wary of complex terrain.

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.

The high pressure has returned to our area bringing clear skies and warm temperatures. Ridgetop winds should remain light for the next few days. There is still a small chance for snow tomorrow as a disturbance moves by us to the east.

As far as our snowpack goes, there is not much new to report. The snowpack is still mostly made up of crusts and facets. On the southerly slopes the faceting process has pretty much stopped, and consistent melt-freeze cycles are causing these slopes to trend towards becoming more stable. On the other hand the NW-N-NE slopes do not get much sun, and as a result the surface temperatures are much colder. These conditions continue to promote facet formation both within the snowpack and near the surface of the snowpack. There is also some surface hoar forming on these aspects. As the snow near the surface turns into weak , "sugary", unconsolidated, facets, some of the treed mid elevation northerly slopes are starting to see an improvement in the sliding conditions. Unfortunately, these weak sugary grains on the surface will not support much additional load. So unless conditions change before the next snowfall, this layer could easily become a failure layer. The weakening trend is also affecting the crusts and other dense layers that have been providing strength and stability to the snowpack. Over the last few days layer bonding tests along the Sierra Crest and in the Mt. Rose area have started to show failures between some of the upper crust layers and the weak faceted snow around them resulting from moderate force. Last week these same layer interfaces were not failing unless one applied much greater force during the tests. In some of these areas there are still a few of the hard slabs left by the strong easterly winds sitting on top of these facet / crust interfaces. Right now collapse at this interface in response to human triggers is unlikely, but not outside the realm of possibility.

No avalanche activity was reported yesterday.

The bottom line: Avalanche danger is LOW for all elevations and aspects. Remember that low danger does not mean no danger. Even though human triggered avalanches are unlikely, there are a few small, isolated areas of instability on NW-N-NE aspects, 35 degrees and steeper. Continue to practice safe travel techniques like traveling one at a time through avalanche terrain and be especially wary of complex terrain.

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

Andy Anderson, Avalanche Forecaster
Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet):
20 deg. F
Max. temperature at Sierra Crest past 24 hours:
34 deg. F
Average wind direction at Sierra Crest past 24 hours:
easterly
Average wind speed at Sierra Crest past 24 hours:
15-25 mph
Maximum wind gust at Sierra Crest past 24 hours:
48 mph
New snow fall at 8,200 feet past 24 hours:
0 inches
Total snow depth at 8,200 feet:
34 inches
Mountain Weather Forecast For Tuesday:
Partly cloudy skies with a chance of snow flurries.
Temperature forecast for 8,000 to 9,000 feet:
27-33 deg. F
Ridgetop winds forecast for the Sierra Crest:
easterly 10-15mph
Snowfall expected in the next 24 hours:
Trace
2 Day Mountain Weather Forecast:

7000 to 8000 Feet
Tonight, clear this evening and becoming partly cloudy later. Lows around 20 degrees F. East winds 10 to 20 mph. Tuesday, partly cloudy skies with daytime highs 33 to 39 degrees F and a chance of snow flurries. Light and variable winds are expected.

Above 8000 Feet
Tonight, clear this evening and becoming partly cloudy later. Lows around 20 degrees F. East winds 10 to 15 mph. Tuesday, partly cloudy skies with daytime highs 27 to 33 degrees F and a chance of snow flurries. East winds at 10-15 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:
	Monday:	Monday Night:	Tuesday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.
For 8000-9000 ft:
	Monday:	Monday Night:	Tuesday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.