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 Saturday, January 13, 2007 at 6:43 am

Cold arctic air is firmly in place across the forecast area. Lingering snow showers from yesterday have moved out of the area leaving clear skies this morning. Another shot of cold air will move through the forecast area tonight, keeping air temperatures cold for the next several days. Ridgetop winds remain easterly this morning and are expected to ease slightly and shift to northerly later today, ahead of the approaching cold air mass. Some light upslope snowfall is possible for the eastern half of the forecast area Sunday night.

Light snowfall up to 1 inch fell during the day yesterday. Very small pockets of shallow wind slab have formed in lee and cross loaded areas on a variety of aspects near and above treeline. These small slabs may fail 1-2 inches below the snow surface today, but do not pose a significant threat to backcountry travelers. These slabs are very small in size and are not expected to propagate over any significant distance. Cold air temperatures are penetrating into the upper snowpack, creating the proper vapor pressure to fuel the near surface faceting process. In the short term, this will keep surface snow unconsolidated in near and below treeline areas that are void of hard slabs. In the long term, prolonged clear and cold weather will weaken the upper snowpack at all elevations, creating the potential for greater instability when the next large storm arrives.

Snow surface conditions remain variable by aspect and elevation. Sun and warm temperatures last week left melt-freeze crust in sun exposed areas on SE-S-SW aspects, especially below 8,500'. NW-N-NE aspects have well defined stable hard slabs above treeline and lingering areas of nice unconsolidated snow below treeline in wind protected areas. On the E and W aspects, expect to find highly mixed snow surface conditions ranging from bare ground, crust, ice, and hard slab, to isolated pockets of unconsolidated snow.

Avalanche danger is LOW for all elevations and aspects.

Brandon Schwartz, Avalanche Forecaster

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Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet): 5 deg. F
Max. temperature at Sierra Crest past 24 hours: 6 deg. F
Average wind direction at Sierra Crest past 24 hours: Easterly
Average wind speed at Sierra Crest past 24 hours: 56 mph
Maximum wind gust at Sierra Crest past 24 hours: 89 mph
New snow fall at 8,200 feet past 24 hours: 1 inch
Total snow depth at 8,200 feet: 40 inches

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Mountain Weather Forecast For Today:
Sunny and cold.
Temperature forecast for 8,000 to 9,000 feet: 10 - 15 deg. F
Ridgetop winds forecast for the Sierra Crest: Northeasterly 20 - 35 mph, G60 mph
Snowfall expected in the next 24 hours: 0 inches

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2 Day Mountain Weather Forecast:
7000 to 8000 Feet
Today, sunny skies with daytime highs 18 to 23 degrees F. Northeast winds 10 to 20 mph. Overnight, partly cloudy with lows 12 to 17 degrees F. Northeast winds at 10 to 20 mph. Sunday will be partly cloudy with daytime highs 20 to 25 degrees F. Northeast winds at 15 to 25 mph are expected.

Above 8000 Feet
Today, sunny skies with daytime highs 10 to 15 degrees F. Northeast winds 20 to 35 mph gusting to 60 mph. Overnight, partly cloudy with lows 7 to 12 degrees F.. North winds at 15 to 25 mph gusting to 50 mph. Sunday will be partly cloudy with daytime highs 17 to 22 degrees F. Northeast winds at 25 to 35 mph gusting to 60 mph are 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:
	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.