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 Monday, December 18, 2006 at 7:01 am

Thanks to everyone who came out yesterday to support the avalanche center. We really appreciate all of you who have donated funds to us and who bought Mt. Rose tickets. Thanks to all of you yesterday was a financial success! We still don't have enough money to cover costs for the season yet, but with yesterday's event we will be able to keep the center going at full speed through our next fundraiser. Our next fundraiser is another ski day on January 21st at Kirkwood. Tickets for that day will go on sale a couple of weeks prior to the 21st. Your donations and support are what keeps the avalanche center going, thanks!

A ridge of cold high pressure will remain over forecast area through Thursday. Temperatures will stay low with highs in the in twenties and lows in the single digits. The winds have shifted to the east northeast and are moderate. They will gain strength through the day and overnight, but by tomorrow they will change to a light north wind.

The east northeast winds are scouring our N-NE-E starting zones and depositing the snow onto the S-SW-W aspects. This scouring will leave behind the hard melt-freeze crust left over from the warmth and rain that we had earlier. While the temperatures remain cold, it will be very hard for any new snow to bond to this crust, and the existing snow will start to weaken again. On many of our northerly aspects and more shaded slopes, we will start to see near surface faceting and maybe some surface hoar in the more wind sheltered areas. These layers could easily pose a problem during the next storm cycle. The longer that the weather stays cold and clear, the more widespread and well developed these layers will be. Without deep snow cover to insulate the snow grains within the pack, faceting will also start occurring in the layers that have already been buried. Above 8500' the depth hoar and near crust facets will continue to mature and weaken. The strong melt-freeze crust above these layers will also start to lose strength. Even the strong refrozen snowpack below 8500' will start to facet in this weather. Hopefully, the weather will change before the snowpack loses too much strength. Right now the likelyhood of triggering any avalanches is small, but we will develop several layers that could be potential failure layers during our next storm.

Near and above treeline, avalanche danger is LOW. Below treeline, avalanche danger is LOW.

Andy Anderson , Avalanche Forecaster
Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet):
6 deg. F
Max. temperature at Sierra Crest past 24 hours:
20 deg. F
Average wind direction at Sierra Crest past 24 hours:
east northeast
Average wind speed at Sierra Crest past 24 hours:
35 mph
Maximum wind gust at Sierra Crest past 24 hours:
61 mph
New snow fall at 8,200 feet past 24 hours:
0 inches
Total snow depth at 8,200 feet:
25 inches
Mountain Weather Forecast For Today:
Sunny and cold.
Temperature forecast for 8,000 to 9,000 feet:
21-29 deg. F
Ridgetop winds forecast for the Sierra Crest:
east 10- 20 mph, G 35 mph
Snowfall expected in the next 24 hours:
0 inches
2 Day Mountain Weather Forecast:

7000 to 8000 Feet
For today, clear and cold. Daytime highs of 25 to 33 degrees F. Winds out of the east at 10-20 mph increasing in the afternoon. Gusts to 30 mph. Overnight lows 2-12 degrees F with clear skies. Winds east at 10-15mph. Tuesday will be sunny with daytime highs near 30 degrees F. The winds will moderate and shift to the north at 10-15 mph.

Above 8000 Feet
For today, clear and cold. Daytime highs of 21 to 29 degrees F. Winds out of the east at 10-20 mph increasing in the afternoon. Gusts to 35 mph. Overnight lows 7-17 degrees F with clear skies. Winds east at 30-40mph with gusts to 60 mph. Tuesday will be sunny with daytime highs near 27 degrees F. The winds will moderate and shift to the north at 10-15 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:
	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.