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 14, 2007 11:23 AM
Click here for a detailed map of the SAC forecast area

No danger rating issued, limited data.
Today's Advisory:
We are still working with limited data. However, natural and human triggered avalanche activity in not expected today. Shallow buried objects such as rocks, down trees, and stumps remain the major threat to backcountry travelers.

The cold northeasterly flow that has been sitting over the forecast area all week should start to shift today. A weak low pressure system moving through the Pacific Northwest should bring southwest winds and a few clouds to the forecast area over the weekend. The winds should start to shift to the southwest tonight. Slightly warmer temperatures are forecast over the next few days. Along the crest and in the Mount Rose area the temperatures have already started to increase. This change in the weather signals the beginning of a new pattern that could bring some precipitation to the forecast area next week. Stay tuned and cross your fingers!
The week of moderate to strong east winds has stripped many of the traditional N-NE-E facing avalanche starting zones near and above treeline back to bare ground. The more protected and lower elevation areas have shallow snow cover that is about 14 inches deep. Observations and remote snow depth sensors show 6 to 10 inches of settlement has occurred since the end of the storm on December 7th. In general the snowpack consists of layer of more dense snow near the ground that has a less dense layer on top of it. The combination of a shallow snowpack and consistently cold temperatures should cause some facet formation in this snowpack. A snowpit from a north aspect at 8700' above Tahoe Meadows already showed facets and depth hoar beginning to form near the ground on December 9th. These weak, sugary snow grains that have formed in the snowpack during this cold, dry spell will be a layer to watch during the next storms.

Sufficient anchoring of a shallow snowpack is keeping instability from forming in many areas. As more snow accumulates the anchors will have less and less influence. These anchors also have a negative side. Right now they are only buried under a few inches of unconsolidated snow making them hard to see but easy to hit.

The bottom line: At this time, we are still working with limited data. However, natural and human triggered avalanche activity in not expected today. Collision with shallow buried objects such as rocks, down trees, and stumps remains the major 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.
Andy Anderson, Avalanche Forecaster

Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet): 23 deg. F
Max. temperature at Sierra Crest past 24 hours: 23 deg. F
Average wind direction at Sierra Crest past 24 hours: East northeast
Average wind speed at Sierra Crest past 24 hours: 22 mph
Maximum wind gust at Sierra Crest past 24 hours: 37 mph
New snow fall at 8,200 feet past 24 hours: 0 inches
Total snow depth at 8,200 feet: 14 inches
Mountain Weather Forecast For Today:
Partly cloudy to clear skies.
Temperature forecast for 8,000 to 9,000 feet: 31 to 37 deg. F.
Ridgetop winds forecast for the Sierra Crest: Northeast at 15 to 25 mph shifting to the northwest at 10 mph in the 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 33 to 39 deg. F. Winds should be light and out of the northeast.

Tonight, partly cloudy skies in the evening then becoming mostly cloudy overnight with overnight lows 15 to 21 deg. F. Winds out of the southwest at 10 to 20 mph expected.

For Saturday, partly cloudy skies with daytime highs around 36 deg. F. Winds out of the southwest at 15 to 20 mph with gusts to 30 mph expected.

Above 8000 Feet:
Today, partly cloudy in the morning, then clearing. Daytime highs 31 to 37 deg. F. Winds should out of the northeast at 15 to 25 mph shifting to the northwest at 10 mph in the afternoon.

Tonight, partly cloudy skies in the evening then becoming mostly cloudy overnight with overnight lows around 18 deg. F. Winds out of the southwest at 15 to 25 mph expected.

For Saturday, partly cloudy skies with daytime highs around 35 deg. F. Winds out of the southwest at 15 to 25 mph with gusts to 35 mph expected.

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