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 January 3, 2008 6:45 AM
Click here for a detailed map of the SAC forecast area

low avalanche danger
Today's Advisory:

Avalanche danger is LOW for all elevations and aspects. Normal caution is advised. Avalanche danger is expected to increase significantly during the evening and overnight hours, following the onset of precipitation.

Strong west to southwest winds are affecting the forecast area this morning. The air temperature inversion the was observed over the past two days has been broken down by the increasing winds. Thickening cloud cover will occur today as a series of major storm systems approach the area. Snowfall and valley rain are expected to begin late today, intensifying overnight into very heavy snowfall and very strong winds (blizzard conditions) for Friday.

An overall stable snowpack exists throughout the forecast area at this time. Around 2 to 3 feet of snow is on the ground on NW-N-NE-E aspects above 6,500' to 7,000' in most areas. A basal layer of faceted snow crystals exists at the ground in all areas. Along the Sierra Crest, zero to 2 crust layers exist near the surface, created by melt-freeze conditions and the spotty Dec. 28 rain event. Over the last few days, snow stability tests performed along the northern portion of the Sierra Crest have shown good layer bond strength within the snowpack, despite the presence of the above mentioned relative weak layers. On SE-S-SW-W aspects, the snowpack is shallow following repeated wind scouring and periods of melting.

The most enjoyable snow surface conditions are still found on treed north aspects above 7,000'. A mix of melt-freeze crusts and hard wind scoured snow surfaces are found in most other areas. Expect a significant change in conditions during the next 24 hours.

The bottom line: Avalanche danger is LOW for all elevations and aspects. Normal caution is advised. Avalanche danger is expected to increase significantly during the evening and overnight hours, following the onset of precipitation.

Please send us your snow, weather, and avalanche observations by clicking the submit observations link on our contact page.

Brandon Schwartz, Avalanche Forecaster

Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet): 24 deg. F
Max. temperature at Sierra Crest past 24 hours: 35 deg. F
Average wind direction at Sierra Crest past 24 hours: Westsouthwest
Average wind speed at Sierra Crest past 24 hours: 40 mph
Maximum wind gust at Sierra Crest past 24 hours: 92 mph
New snow fall at 8,200 feet past 24 hours: 0 inches
Total snow depth at 8,200 feet: 30 inches

Mountain Weather Forecast For Today:
Cloudy skies with isolated snow showers in the afternoon.
Temperature forecast for 8,000 to 9,000 feet: 25 to 29 deg. F
Ridgetop winds forecast for the Sierra Crest: Southwest at 40 to 55 mph with gusts to 85 mph.
Snowfall expected in the next 24 hours: 4 to 8 inches

2 Day Mountain Weather Forecast:

7000 to 8000 Feet:
Today, cloudy skies with isolated snow showers in the afternoon. Daytime highs 35 to 41 deg. F. South winds at 20 to 35 mph, with gusts to 50 mph.

Tonight, cloudy skies with a chance of snow in the evening. Snow after midnight with 2 to 6 inches of accumulation. Overnight lows 28 to 32 deg. F. Southwest winds at 20 to 30 mph with gusts to 45 mph, increasing to 30 to 40 mph with gusts to 65 mph after midnight.

For Friday, cloudy skies with heavy snowfall and blizzard conditions. Snow accumulation 20 to 26 inches. Snow level rising to near 7,000'. Daytime highs remaining near 32 deg. F. Southwest winds at 30 to 50 mph with gusts to 80 mph.

Above 8000 Feet:
Today, cloudy skies with isolated snow showers in the afternoon. Daytime highs 24 to 29 deg. F. Southwest winds at 40 to 55 mph, with gusts to 85 mph.

Tonight, cloudy skies with a chance of snow in the evening. Snow after midnight with 4 to 8 inches of accumulation. Overnight lows 24 to 26 deg. F. Southwest winds at 50 to 65 mph with gusts to 120 mph.

For Friday, cloudy skies with heavy snowfall and blizzard conditions. Snow accumulation 20 to 30 inches. Daytime highs remaining near 30 deg. F. Southwest winds at 65 to 85 mph decreasing to 55 to 75 mph in the afternoon. Wind gusts up to 145 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.