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, March 2nd, 2007 at 6:48 am

The bottom line: Avalanche danger near and above treeline is MODERATE with isolated pockets of CONSIDERABLE forming on wind loaded SW-W-NW aspects 35 degrees and steeper. Below treeline, avalanche danger is LOW.

Cloud cover has decreased over the forecast area overnight. Some lingering cloud cover will exist today at the upper elevations with breaks of sun expected. Air temperatures are expected to warm a bit each day through the weekend. A ridge of high pressure will build into the forecast area overnight for Saturday. This high pressure is expected to move quickly to the east as a weak weather system moves in off the Pacific Ocean on Sunday. Ridgetop winds have shifted to easterly overnight and are expected to increase in wind speed as the day progresses.

The recent storm snow has bonded well to the old snow surface below it. Weaknesses that existed within the storm snow over that past few days have decreased significantly as continued layer bond strength has been observed. Around 3-5 inches of settlement has been observed in the past 24 hours, helping to further increase snowpack stability. Plenty of snow remains available for wind transport above treeline. Yesterday, layer bonding tests yielded moderate to hard shears within the top 5 feet (150cm) of the snowpack. Gradually, warming air temperatures over the next few days are expected to contribute to snowpack stability, rather than instability from more rapid warming events immediately following new snowfall that begin to occur this time of year.

Cornices remained sensitive to human triggered collapse yesterday. Small pockets of unstable surface snow up to 1 foot deep were observed directly below cornice features. Surface snow was significantly more stable further down slope below cornices.

Ridgetop winds that shifted to easterly overnight will cause wind loading on SW-W-NW aspects today. The snow above treeline is already wind affected from the recent storm and will form cohesive slabs very quickly. East winds will erode and help to stabilize cornice features today. New areas of snowpack instability will form. New surface slabs up to 1 foot deep are expected to form today in wind loaded areas.

Human triggered avalanches are possible today on wind loaded SW-W-NW aspects, 35 degrees and steeper. Pockets of natural avalanche activity are not impossible in heavily wind loaded areas today, especially by this afternoon.

The bottom line: Avalanche danger near and above treeline is MODERATE with isolated pockets of CONSIDERABLE forming on wind loaded SW-W-NW aspects 35 degrees and steeper. Below treeline, avalanche danger is LOW.

At this time, we are still short $4,000 in funding for our operating budget this winter. If you use this service with any regularity and would like to continue to do so, please show your financial support for the Sierra Avalanche Center. You may 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. A graph showing the amount of fundraising completed this season and our overall budget is available by clicking here. The financial support already received this winter from a variety of users is greatly appreciated.

Brandon Schwartz, Avalanche Forecaster

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Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet): 12 deg. F
Max. temperature at Sierra Crest past 24 hours: 21 deg. F
Average wind direction at Sierra Crest past 24 hours: Westerly shifting to easterly
Average wind speed at Sierra Crest past 24 hours: 20 mph
Maximum wind gust at Sierra Crest past 24 hours: 37 mph
New snow fall at 8,200 feet past 24 hours: 0-1 inches
Total snow depth at 8,200 feet: 105 inches

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Mountain Weather Forecast For Today:
Partly to mostly cloudy skies.
Temperature forecast for 8,000 to 9,000 feet: 26 to 31 degrees F.
Ridgetop winds forecast for the Sierra Crest: Easterly 20-35 mph, gusting to 45 mph.
Snowfall expected in the next 24 hours: 0 inches

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2 Day Mountain Weather Forecast:
7000 to 8000 Feet
Today, partly to mostly cloudy skies. Daytime highs around 36 degrees F. North winds at 10 to 20 mph. Tonight, partly cloudy with overnight lows 15 to 23 degrees F. Northeast winds at 10 to 15 mph. Saturday, sunny skies with daytime highs 42 to 48 degrees F. East winds at 10 to 20 mph are expected.

Above 8000 Feet
Today, partly to mostly cloudy skies. Daytime highs around 31 degrees F. East winds at 20 to 35 mph with gusts to 45 mph. Tonight, partly cloudy with overnight lows 16 to 22 degrees F. East winds at 20 to 30 mph with gusts to 45 mph. Saturday, sunny skies with daytime highs 37 to 43 degrees F. East winds at 10 to 20 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.