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 Sunday, April 8th, 2007 at 6:42 am

The bottom line: Early this morning, avalanche danger is LOW for all elevations and aspects. As daytime warming occurs, avalanche danger will rise to MODERATE above 8,000' on E-SE-S-SW aspects 35 degrees and steeper. Below 8,000', avalanche danger will rise to MODERATE on all snow covered aspects, 35 degrees and steeper.

The weak weather system that moved through the forecast area yesterday is moving off to the east this morning. Clearing skies will occur today as weak high pressure moves over the area. Ridgetop winds have gradually shifted from westsouthwesterly to westerly during the past 24 hours. Winds speeds have decreased overnight and are expected to become light today before increasing again overnight. The next weather system expected to bring precipitation to the forecast area is forecasted to arrive on Wednesday.

Overnight air temperatures fell near freezing overnight at the 8,500' level along the Sierra Crest. Despite periods of mid level cloud cover that limited radiational cooling, a decent surface refreeze is expected in this area. Above 9,000' in the Mount Rose area, a solid surface refreeze occurred last night as air temperatures fell well below freezing. Conditions this morning are much improved over 24 hours ago when only a very thin and weak surface refreeze was observed yesterday morning.

Wet snow below a surface crust exists on all E-SE-S-SW-W aspects throughout the forecast area. Isolated areas of a more winter like snowpack exist above 9,000' on NW-N-NE aspects. Despite May like air temperatures for the past month, the sun angle of March and early April has kept solar radiation on steep northerly aspects to a minimum. Excellent corn snow conditions can be found on a variety of aspects during the morning hours.

The snow surface will soften rapidly this morning in sun exposed areas, especially below 8,000' where only a weak refreeze of the snow surface occurred overnight. Once the supportable surface crust has melted today, snowpack instability will rapidly increase. Human triggered avalanches will become possible today above 8,000' on E-SE-S-SW aspects, 35 degrees and steeper. Below 8,000', human triggered avalanches will become possible on all snow covered aspects, 35 degrees and steeper.

Keep in mind that when boot penetration in wet snow exceeds boot top height, human triggered wet snow avalanches are possible in that area. Step off of your equipment on a regular basis to check boot penetration. When evidence of wet snow instability such as deep boot penetration or pinwheels larger than 1 foot in diameter develop, move to a less sun affected aspect or call it a day.

The bottom line: Early this morning, avalanche danger is LOW for all elevations and aspects. As daytime warming occurs, avalanche danger will rise to MODERATE above 8,000' on E-SE-S-SW aspects 35 degrees and steeper. Below 8,000', avalanche danger will rise to MODERATE on all snow covered aspects, 35 degrees and steeper.

We will raffle a BCA backpack, beacon, shovel, and probe package on April 17th as a way to say thanks to everyone who has sent us a donation in the mail or via Pay Pal this season. All individuals who have donated $10 or more to SAC are automatically entered in this raffle. Thanks to all of our sponsors, the ski days, and everyone who has donated funding this winter, we have met our operating budget for this season and have a start on next year's funding. For more details about our financial situation please click here. An additional thank you to everyone who supported us at the Heavenly Pro Patrol fundraiser, where SAC was a chosen beneficiary of the evening's events.

Brandon Schwartz, Avalanche Forecaster

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Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet): 31 deg. F
Max. temperature at Sierra Crest past 24 hours: 45 deg. F
Average wind direction at Sierra Crest past 24 hours: Westsouthwesterly shifting to westerly
Average wind speed at Sierra Crest past 24 hours: 34 mph
Maximum wind gust at Sierra Crest past 24 hours: 65 mph
New snow fall at 8,200 feet past 24 hours: 0 - trace inches
Total snow depth at 8,200 feet: 56 inches

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Mountain Weather Forecast For Today:
Mostly cloudy in the morning, becoming partly cloudy in the afternoon.
Temperature forecast for 8,000 to 9,000 feet: 42 - 52 degrees F.
Ridgetop winds forecast for the Sierra Crest: Westerly at 10 to 20 mph, gusting 30 mph
Snowfall expected in the next 24 hours: 0 inches

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2 Day Mountain Weather Forecast:
7000 to 8000 Feet:
Today, mostly to partly cloudy skies with daytime highs 51 to 57 degrees F. West winds at 10 to 20 mph, gusting to 25 mph in the afternoon. Tonight, clear skies with overnight lows around 30 degrees F. West winds at 15 to 20 mph, shifting to southwest 20 to 30 mph after midnight. Monday, sunny skies with daytime highs 44 to 52 degrees F. Southwest winds at 25 to 35 mph, decreasing to 15 to 25 mph in the afternoon are expected.

Above 8000 Feet:
Today, mostly to partly cloudy skies with daytime highs 42 to 52 degrees F. West winds at 10 to 20 mph, gusting to 30 mph. Tonight, clear skies with overnight lows around 29 degrees F. West winds at 15 to 25 mph, increasing to 30 to 45 mph with gusts to 60 mph after midnight. Monday, sunny skies with daytime highs 38 to 46 degrees F. West winds at 30 to 50 mph, decreasing to 20 to 30 mph in the afternoon 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:
	Sunday:	Sunday Night:	Monday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.
For 8000-9000 ft:
	Sunday:	Sunday Night:	Monday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.