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 Sunday, December 31, 2006 at 7:00 am

The inversion will start to lift today as the high pressure moves farther east. There is a small chance for some snow (1"-2") Sunday night as a very weak low pressure moves across the forecast area. The winds will continue to be calm and should shift to the southwest ahead of this small disturbance.

The warm temperatures above 7000' have helped the snowpack consolidate. The recent windslabs are bonding quite well to the weaker layers below them, which in turn are starting to strengthen. Today this trend will continue and our snowpack will gain strength. The hard windslabs on the NW aspects will become increasingly hard to trigger. Still a large trigger such as a snowmoblie or two, a large cornice failure, or several skiers or boarders in the right spot on a steep slope could cause the windslabs to fail. The likely trigger points include areas where the slab is thin, just below cornices and cliffs, shallowly buried rocks, and convex rollovers. Due to the inversion the lower elevations have stayed cold. The cold, clear, calm conditions have allowed for some surface hoar to form. In most places the surface hoar will probably be destroyed today as the inversion lifts or as the next warm storm comes through. The areas that it could persist will be on shaded wind sheltered north aspects. These will be slopes that have the potential to surprise us later after we get more snow.

There is still some great, soft snow left over from the storm to play in. The best places to find it are on the mid elevation NW-N-NE aspects with good tree cover to protect the snow from the wind.

Today the avalanche danger is LOW in areas that are not wind affected. The avalanche danger is MODERATE on windloaded slopes steeper than 35 degrees. The most likely aspects for these hard windslabs are the NW slopes.

Andy Anderson, Avalanche Forecaster.

Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet):
39 deg. F
Max. temperature at Sierra Crest past 24 hours:
50 deg. F
Average wind direction at Sierra Crest past 24 hours:
Northeast shifting to west
Average wind speed at Sierra Crest past 24 hours:
10 mph
Maximum wind gust at Sierra Crest past 24 hours:
47 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 Today:
Sunny and warm.
Temperature forecast for 8,000 to 9,000 feet:
44 deg. F
Ridgetop winds forecast for the Sierra Crest:
west at 10-20 mph.
Snowfall expected in the next 24 hours:
0 inches
2 Day Mountain Weather Forecast:

7000 to 8000 Feet
For today, sunny and warm with winds out of the west at 10-15 mph. Daytime highs around 41-47 degrees F. Overnight, mostly cloudy, lows 21 to 29 degrees F. Southwest winds at 10-20 mph. Tomorrow, mostly cloudy with a chance of snow. Daytime highs around 40 degrees F. with winds out of the southwest at 15 to 20 mph.

Above 8000 Feet
For today, sunny and warm with winds out of the west at 10-20 mph. Daytime highs around 44 degrees F. Overnight, mostly cloudy, lows 26 degrees F. Southwest winds at 15-25 mph. Tomorrow, mostly cloudy with a chance of snow. Daytime highs around 36 degrees F. with winds out of the southwest at 20 to 30 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:
	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.