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, April 7th, 2007 at 7:00 am

The bottom line: 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.

A weak weather system will move through the forecast area today. Increasing cloud cover, scattered rain and snow showers, increasing winds, and possible lightning activity are expected. Isolated rain and snow showers are expected to begin late this morning and become more widespread in the afternoon. Snow level for today is forecasted at 8,500'. Ridgetop winds shifted to light westsouthwesterly overnight and are expected to increase to moderate as the day progresses. Yesterday, afternoon cloud build up lead to widespread lightning strikes along the Sierra Crest between Ebbets Pass and Donner Summit beginning around 2:30pm. Less lightning activity is expected today.

Five consecutive nights of above freezing temperatures and thin cloud cover have only allowed for a weak overnight surface refreeze of the snowpack at all elevations. The snow surface was observed to soften rapidly yesterday morning at all elevations on E-SE aspects. In the Mount Rose area, whumphing and collapse without visible propagation was repeatedly observed on a SE aspect of Relay Ridge at 10,000' around 11am. A softened but still supportable surface crust overlying 3-4 feet of wet snow existed in the area at that time. Similar conditions of wet snow below a surface crust exist 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.

Cloud cover and a passing weather system will decrease air temperatures today, but areas of wet snow instability will still form in response to daytime warming, especially with only a weak overnight refreeze occurring last night. 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 warming affected aspect or call it a day.

The bottom line: 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): 36 deg. F
Max. temperature at Sierra Crest past 24 hours: 55 deg. F
Average wind direction at Sierra Crest past 24 hours: Southeasterly shifting to westsouthwesterly
Average wind speed at Sierra Crest past 24 hours: 16 mph
Maximum wind gust at Sierra Crest past 24 hours: 33 mph
New snow fall at 8,200 feet past 24 hours: 0 inches
Total snow depth at 8,200 feet: 56 inches

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Mountain Weather Forecast For Today:
Mostly cloudy to cloudy skies with rain and snow showers.
Temperature forecast for 8,000 to 9,000 feet: 46 - 52 degrees F.
Ridgetop winds forecast for the Sierra Crest: Westsouthwesterly at 20 to 30 mph, gusts 60 mph
Snowfall expected in the next 24 hours: 0 - trace inches above 8,500'

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2 Day Mountain Weather Forecast:
7000 to 8000 Feet:
Today, mostly cloudy to cloudy skies with scattered rain showers. A slight chance of isolated thunderstorms exists for the afternoon. Daytime highs 49 to 59 degrees F. Southwest winds at 10 to 20 mph, gusting to 30 mph. Tonight, mostly cloudy skies with isolated showers in the evening. Overnight lows around 29 degrees F. Southwest winds at 20 to 30 mph, decreasing to 10 to 20 mph after midnight. Sunday, mostly cloudy skies with daytime highs 43 to 49 degrees F. West winds at 10 to 15 mph are expected.

Above 8000 Feet:
Today, mostly cloudy to cloudy skies with scattered rain and snow showers showers. Snow level 8,500'. No measurable new snow accumulation is expected. A slight chance of isolated thunderstorms exists for the afternoon. Daytime highs 46 to 52 degrees F. Westsouthwest winds at 20 to 30 mph, gusting to 60 mph. Tonight, mostly cloudy skies with isolated showers in the evening. Overnight lows around 25 degrees F. Southwest winds at 25 to 35 mph, decreasing to 15 to 25 mph after midnight. Sunday, mostly cloudy skies with daytime highs 36 to 42 degrees F. West winds at 15 to 20 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.