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 Thursday, December 14, 2006 at 5:31 am

Our SAC ski day tickets for Mt. Rose are not selling very well. We need your help! This is one of our two largest fund raisers for this season. We currently only have enough funds in the bank to operate through January. If you use this page with any regularity, please help to keep SAC alive and running by purchasing a SAC ski day lift ticket. Even if you do not plan on skiing that day, your donation will help to keep the center running through this season. If you are in a position to purchase more than one ticket, please do so. Without your support, we will be laid off, the center will close, and this product will cease to exist. Click here to go to Snowbomb.com and purchase your ticket today! The skiing is getting better by the minute, especially at the upper elevations.

Snow levels will remain high during the day today and then will rapidly drop as a strong cold front moves in this evening. Forecasts are predicting anywhere from 6"-16" of snow accumulation tonight. The winds will increase dramatically throughout the day to a consistent SW wind at 40-45 MPH with gusts to 90 MPH by this afternoon. Expect lots of wind transport of the snow that falls tonight.

It has been above freezing since yesterday morning at the upper elevations and even longer at the lower elevations. In many places the snowpack has become isothermal, and water is percolating to the ground. This water and warmth is consolidating the snowpack. When the temperatures drop tonight and the water in the snowpack freezes, all the layers that were once there will be cemented together and act as one. We will have a very solid, supportable base. The wet snow also stuck to many of the uncovered obstacles in our starting zones and will help give us much more widespread and consistent snow cover. This base will help to dramatically improve the skiing as we get more snow on top of it. During the day today as temperatures stay above freezing and water continues to saturate the snowpack, the snowpack will stay unconsolidated. There is a chance of triggering some loose snow avalanches or wet slabs today. Any of these slides will still be small and isolated because of huge variation in snow depth and anchoring across most of our starting zones. If you are out today, hop off your skis often and check to see how far you sink into the wet snow. If you are sinking further than your boot tops get off of any steep terrain as this indicates that there is very little cohesion in a significant portion of the snowpack, and a small additional load could be all that is needed to trigger a wet slab. Also, watch for other signs of wet snow instability such as other wet slides, large pinwheels, or the snow collapsing around you. The most suspect slopes will be those that had consistent snow cover before this last storm and are steeper than 35 degrees. These will be mostly on NW-N-NE-E windloaded aspects or in wind sheltered areas that have held snow.

Near and above treeline, avalanche danger is MODERATE on those steep NW-N-NE-E windloaded aspects and on an other steep slopes that had consistent snowcover before the storm. Below treeline, avalanche danger MODERATE on any steep slopes that had consistent snowcover before the storm.

Remember that even though you are unlikely to trigger any large avalanches, a small avalanche can be disastrous depending on the terrain. Be aware of secondary exposures such as rockbands, cliffs, gullies, and creek beds, where the consequences of being caught in a small avalanche are greatly magnified.

Andy Anderson , Avalanche Forecaster

Today's Central Sierra Weather Observations:
0500 temperature at Sierra Crest (8,700 feet):
32 deg. F
Max. temperature at Sierra Crest past 24 hours:
34 deg. F
Average wind direction at Sierra Crest past 24 hours:
westsouthwesterly
Average wind speed at Sierra Crest past 24 hours:
35 mph
Maximum wind gust at Sierra Crest past 24 hours:
70 mph
New snow fall at 8,200 feet past 24 hours:
trace
Total snow depth at 8,200 feet:
16 inches
Mountain Weather Forecast For Today:
Cloudy skies with rain showers.
Temperature forecast for 8,000 to 9,000 feet:
35-40 deg. F
Ridgetop winds forecast for the Sierra Crest:
southwest at 30-45 mph, G 90 mph
Snowfall expected in the next 24 hours:
up to 16 inches
2 Day Mountain Weather Forecast:

7000 to 8000 Feet
For today, cloudy skies with rain showers. Daytime highs of 40 to 45 degrees F. Tonight lows 29 to 33 degrees F. Snow showers starting this evening with accumulations up to 10" overnight . Winds out of the southwest at 35-45 mph with gusts to 70 mph. Friday will be mostly cloudy a chance of snow with accumulations of 1-2". Daytime highs near 35 in the morning then falling to 25 to 30 in the afternoon. Winds out of the southwest at 30-40mph with gusts to 60 mph.

Above 8000 Feet
For today, cloudy skies with rain showers. Daytime highs of 35 to 40 degrees F. Overnight lows 27 degrees F. Snow showers starting this evening with accumulations up to 16" along the crest. Winds out of the southwest at 50-60 mph with gusts to of 100-115 mph. Friday will be mostly cloudy a chance of snow with accumulations of 2-4". Daytime highs near 30 in the morning then falling to 18 to 25 in the afternoon. Winds out of the southwest at 40-50mph with gusts to 100 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:
	Thursday:	Thursday Night:	Friday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.
For 8000-9000 ft:
	Thursday:	Thursday Night:	Friday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.