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, February 6th, 2007 at 4:32 pm

The bottom line: Avalanche danger is LOW for all elevations and aspects. Avalanche danger is expected to begin to increase significantly Wednesday afternoon and remain elevated into next week.

We will update the financial graph as soon as we get the final numbers from our recent fundraiser event. We still have not made the budget for this year are a long way from the total fundraising goal. If you like what we do and want to see it continue, 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.

High pressure that has dominated the forecast area for the past month is moving to northern Alaska. This will allow moisture to stream through the middle latitudes and into Central California beginning late tomorrow morning. Wet weather and fluctuating snow levels are expected to last into next week. Ridgetop winds over the Sierra Crest increased during the day today ahead of the approaching storm system. Maximum observed air temperatures at the upper elevations were about 10 degrees F. cooler today than for the past two days.

A highly variable snowpack exists throughout the forecast area. Some areas along the Sierra Crest, especially sun exposed aspects below 8,000' and other low elevation areas have gained significant snowpack strength over the past few days. Other areas along the Sierra Crest, such as shaded northerly aspects in the 7,500'-8,500' range, are still showing weakness within faceted layers and at crust interfaces. These areas have only developed thin melt-freeze surface crusts over the past several days. Faceted snow is still highly visible near the snow surface and deeper within the existing snowpack in these areas. Wind protected areas above 8,500' are showing a deeper and stronger snowpack. Wind scoured areas along ridgelines hold a shallow snowpack with weak facets still evident. Faceted snow of moderate weakness is evident in most snow covered areas in Mount Rose zone, especially on northerly aspects above 8,500'.

Some of these areas are in good condition to handle new snow loading. Other areas are not. The existing snowpack within the forecast area is very different than the snowpack observed in February of recent winters. Significant avalanche activity is possible during the coming days. Backcountry travelers must prepare for the possibility of snowpack instability that has not been observed in this area in during the past few winters. Very careful observation and route selection will be necessary.

No avalanche activity was reported today.

The bottom line: Avalanche danger is LOW for all elevations and aspects. Avalanche danger is expected to begin to increase significantly Wednesday afternoon and remain elevated into next week.

The next scheduled update to this advisory will occur Wednesday morning.

Brandon Schwartz, Avalanche Forecaster

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

Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet): 36 deg. F
Max. temperature at Sierra Crest past 24 hours: 42 deg. F
Average wind direction at Sierra Crest past 24 hours: southwesterly
Average wind speed at Sierra Crest past 24 hours: 33 mph
Maximum wind gust at Sierra Crest past 24 hours: 72 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 Wednesday:
Cloudy skies. Rain and snow developing by mid morning
Temperature forecast for 8,000 to 9,000 feet: 29 - 34 deg. F
Ridgetop winds forecast for the Sierra Crest: Southwesterly 40 - 50 mph, gusting to 80 mph
Snowfall expected in the next 24 hours: 3 - 6 inches above 8,000'

--------------------------------------------------------------------------------
2 Day Mountain Weather Forecast:
7000 to 8000 Feet
Tonight, mostly cloudy skies with lows 27 to 35 degrees F. South winds at 20 to 30 mph. Wednesday, cloudy skies with snow. Daytime highs around 32 degrees F. Snow level 6,500', lowering to 6,000' in the evening. Winds are forecasted to be out of the southwest at 30 to 45 mph.

Above 8000 Feet
Tonight, mostly cloudy skies with lows around 28 degrees F. Southwest winds at 25 to 35 mph, gusting to 60 mph. Wednesday, cloudy skies with snow. Daytime highs 29 to 34 degrees F. Winds are forecasted to be out of the southwest at 40 to 50 mph, gusting to 80 mph.

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.