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 February 25, 2008 7:00 AM
Click here for a detailed map of the SAC forecast area

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Today's Advisory:

This morning, avalanche danger is MODERATE near and above treeline on NW-N-NE-E aspects, 37 degrees and steeper. Below treeline, avalanche danger is LOW. Areas of CONSIDERABLE danger will develop below 8,000' in sun exposed areas, 37 degrees and steeper in response to daytime warming.

The storm system that brought snow to the forecast area over the past two days and moved off to the east overnight. Clearing skies and warming air temperatures are expected today. New snow amounts from the past 24 hours range from 10 to 15 inches across the forecast area. Storm totals for the past 48 hours range from 25 to 35 inches. Southwest ridgetop winds have decreased from strong to light over the past 24 hours. Winds are expected to shift to the west and then to the north this afternoon. Light to moderate wind speeds are forecast for today.

Yesterday, around 1 foot of higher density (19%) new snow was observed on top of around 1 foot of lower density new snow (12%) at the Alpine Meadows snow study plot. Layer bonding tests at that location yielded easy force shears. Similar conditions were observed on Tamarack Peak (Mount Rose area). However, snowpit data and layer bonding tests taken from N and NE aspects at 9,200-9,400' on Tamarack Peak yielded moderate force shears within the lower density new snow layer. No evidence of fracture propagation was observed in the snowpits or on test slopes. Near the Sierra Crest, a natural avalanche occurred along Hwy 89 near the intersection of Alpine Meadows Road around mid day. The avalanche released from a steep west aspect in an open area below treeline. Avalanche debris 1 to 2 feet deep were observed on the road. No other information is known about this avalanche.

With the end of new snow loading occurring during the overnight hours, the snowpack will have had some opportunity to increase in layer bond strength. Some pockets of instability are expected to linger this morning on NW-N-NE-E aspects near and above treeline. Daytime warming is expected to contribute to increasing snowpack instability today. This will occur in sun exposed areas, mainly below 8,000', but is possible at all elevations. Depending on the strength of north to northeast winds that occur today, warming affects above 8,000' will vary. Natural and human triggered avalanches remain possible today.

The bottom line: This morning, avalanche danger is MODERATE near and above treeline on NW-N-NE-E aspects, 37 degrees and steeper. Below treeline, avalanche danger is LOW. Areas of CONSIDERABLE danger will develop below 8,000' in sun exposed areas, 37 degrees and steeper in response to daytime warming.

Please send us your snow, weather, and avalanche observations by clicking the submit observations link on our contact page.

Brandon Schwartz, Avalanche Forecaster

Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet): 18 deg. F
Max. temperature at Sierra Crest past 24 hours: 22 deg. F.
Average wind direction at Sierra Crest past 24 hours: Southwest
Average wind speed at Sierra Crest past 24 hours: 53 mph
Maximum wind gust at Sierra Crest past 24 hours: 102 mph
New snow fall at 8,200 feet past 24 hours: 10 to 15 inches
Total snow depth at 8,200 feet: 110 inches

Mountain Weather Forecast For Today:
Partly cloudy in the morning, then clearing.
Temperature forecast for 8,000 to 9,000 feet: 30 to 34 deg. F
Ridgetop winds forecast for the Sierra Crest: West at 15 to 25 mph with gusts to 40 mph. Winds shifting to north at 10 to 15 mph with gusts to 25 mph by afternoon.
Snowfall expected in the next 24 hours: 0 inches

2 Day Mountain Weather Forecast:

7000 to 8000 Feet:
Today, partly cloudy in the morning, then clearing. Daytime highs 35 to 41 deg. F. West winds at 10 to 15 mph, shifting to the northeast in the afternoon.

Tonight, clear skies with overnight lows 18 to 24 deg. F. East winds around 10 mph in the evening, becoming light.

For Tuesday, sunny skies with daytime highs around 45 deg. F. Light winds expected.

Above 8000 Feet:
Today, partly cloudy in the morning, then clearing. Daytime highs around 33 deg. F. West at 15 to 25 mph with gusts to 40 mph. Winds shifting to north at 10 to 15 mph with gusts to 25 mph by afternoon.

Tonight, clear skies with overnight lows 22 to 28 deg. F. East winds at 10 to 15 mph with gusts to 30 mph.

For Tuesday, sunny skies with daytime highs around 43 deg. F. East winds at 10 mph in the morning, becoming light.

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.