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 December 8, 2007 7:05 AM
Click here for a detailed map of the SAC forecast area

Today's Advisory:
At this time we are still working with limited data. However, human and natural triggered avalanche activity is not expected today. Collision with shallow buried objects such as rocks, down trees, and stumps remains the major threat to backcountry travelers.

Cold air is in place over the forecast area this morning. The storm system from Thursday and Friday has moved off to the east and a weak low pressure system is moving down from the north into our area. Cold air temperatures, some light upslope snowfall, and north to northeast ridgetop winds are expected from this system.

Storm totals above 7000' range from 16 to 22 inches along the Sierra Crest with around 20 inches reported in the Mount Rose area. Air temperatures associated with this storm started warm and ended colder. This deposited higher density snow near the ground and lower density snow near the surface. Yesterday, a few very small human triggered sluffs were observed on a wind loaded north aspect near the summit of Mount Rose Highway. Minimal slab formation was observed on the N-NE-E aspects near and above treeline in the Mount Rose area. Snow pit stability tests taken from a variety of protected and wind loaded areas on Tamarack Peak (Mount Rose area) and a few miles north of Castle Peak (Sierra Crest area) both yielded hard to no shear failure and hard compression failure around 30 cm (1 foot) above ground level. Shear quality was highly irregular in all results. Late Friday afternoon, moderate northeast winds began scouring snow from avalanche start zones on N-NE-E aspects in near and above treeline areas. This removal of snow will reduce the likelihood of avalanche activity. Sufficient anchoring of a shallow snowpack is expected to keep instability from forming near and above treeline on newly wind loaded S-SW-W aspects.

The bottom line: At this time we are still working with limited data. However, natural and human triggered avalanche activity is not expected today. Collision with shallow buried objects such as rocks, down trees, and stumps remains the biggest threat to backcountry travelers.

With so many shallow buried objects, the best option for backcountry travel is touring on snow covered Forest Service roads.

The next update to this advisory will occur when conditions warrant.

Brandon Schwartz, Avalanche Forecaster.

Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet): 10 deg. F
Max. temperature at Sierra Crest past 24 hours: 26deg. F
Average wind direction at Sierra Crest past 24 hours: West shifting to Northeast
Average wind speed at Sierra Crest past 24 hours: 19 mph
Maximum wind gust at Sierra Crest past 24 hours: 51 mph
New snow fall at 8,200 feet past 24 hours: 1 to 2 inches
Total snow depth at 8,200 feet: 20 inches
Mountain Weather Forecast For Today:
Partly to mostly cloudy skies. Increasing cloud cover with snow showers developing, mainly on the east side of the forecast area in the afternoon.
Temperature forecast for 8,000 to 9,000 feet: 15 to 20 deg. F.
Ridgetop winds forecast for the Sierra Crest: Northeast at 20 to 25 mph with gusts to 45 mph.
Snowfall expected in the next 24 hours: 0 to 3 inches
2 Day Mountain Weather Forecast:

7000 to 8000 Feet:
Today, expect sun breaks in the morning with increasing cloud cover and possible snow showers in the afternoon. Snow accumulation up to 2 inches. Daytime highs 18 to 23 deg. F. Northeast winds at 10 to 15 mph with gusts to 25 mph.

Tonight, partly to mostly cloudy skies with scattered snow showers, mainly south of Lake Tahoe. Snow accumulation up to 1 inch. Overnight lows 12 to 16 deg. F. Northeast winds at 10 to 20 mph with gusts to 30 mph.

For Sunday, sun in the morning with increasing high clouds in the afternoon. Daytime highs 24 to 29 deg. F. Northeast winds at 15 to 20 mph with gusts to 35 mph, decreasing in the afternoon.

Above 8000 Feet:
Today, expect sun breaks in the morning with increasing cloud cover and possible snow showers in the afternoon. Snow accumulation up to 2 inches. Daytime highs 15 to 20 deg. F. Northeast winds at 20 to 25 mph with gusts to 45 mph.

Tonight, partly to mostly cloudy skies with scattered snow showers, mainly south of Lake Tahoe. Snow accumulation up to 1 inch. Overnight lows 13 to 20 deg. F. Northeast winds at 20 to 35 mph with gusts to 60 mph.

For Sunday, sun in the morning with increasing high clouds in the afternoon. Daytime highs 22 to 27 deg. F. Northeast winds at 25 to 350 mph with gusts to 50 mph. Northeast winds decreasing to 15 to 25 mph with gusts to 35 mph in the afternoon.

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:
	Saturday:	Saturday Night:	Sunday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.
For 8000-9000 ft:
	Saturday:	Saturday Night:	Sunday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.