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 March 27, 2008 6:42 AM

A map of the SAC forecast area is available on our home page.

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Today's Advisory:

This morning, avalanche danger is LOW for all elevations and aspects. Areas of MODERATE danger will develop below 8,500' on E-SE-S-SW aspects, 40 degrees and steeper in response to daytime warming.

The cold front that moved through the forecast area yesterday has moved off to the southeast this morning. Clearing skies occurred overnight. Southwest ridgetop winds have decreased from strong to moderate in speed during the early morning hours. Winds are expected to become light by this afternoon. Remote sensors are reporting below freezing air temperatures this morning at all locations above 6,000'.

Yesterday, the increased solar radiation associated with this time of year caused significant melting of surface snow in sun exposed areas below 8,500'. Observations made on Rose Knob Peak (Mount Rose area) revealed that ski penetration in wet snow of up to 3 inches occurred on sun exposed E-SE aspects below 8,500' by 11 am. This occurred despite air temperatures only a few degrees above freezing. The snow surface in shadowed areas on the same slopes remained mostly frozen at that time, indicating the influence of direct solar radiation on the snow surface. Ski cuts on small 40 to 42 degree E aspect test slopes at 8,600' yielded a small amount of wet snow sluffing of surface snow. Overnight, clearing skies, radiational cooling, and below freezing air temperatures have allowed wet surface snow that formed yesterday to refreeze in all areas.

Today, melting of surface snow will occur, especially in sun exposed areas below 9,000'. On E-SE-S-SW aspects, well established melt water pathways exist within the snowpack. On northerly aspects, recent snowpit data indicates that free water percolation is limited to the top 1 to 2 feet of the snowpack, well above any basal faceted layers. Instability deep within the snowpack remains unlikely at this time. Areas of wet snow instability will be limited to loose wet surface snow activity in sun exposed areas on very steep terrain. Human triggered wet sluff avalanches will become possible today in very steep sun exposed areas on E-SE-S-SW aspects. Natural avalanche activity remains unlikely.

The bottom line: This morning, avalanche danger is LOW for all elevations and aspects. Areas of MODERATE danger will develop below 8,500' on E-SE-S-SW aspects, 40 degrees and steeper in response to daytime warming.

Public donations to the avalanche center this season are below our fundraising goal. We are going to raffle a beacon, shovel, probe, and backpack package as a way give back to those who donate $100 or more before March 30th. For more information on the raffle and amount of donations received click here.

Brandon Schwartz, Avalanche Forecaster

Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet): 15 deg. F
Max. temperature at Sierra Crest past 24 hours: 28 to 36 deg. F.
Average wind direction at Sierra Crest past 24 hours: Southwest
Average wind speed at Sierra Crest past 24 hours: 54 mph
Maximum wind gust at Sierra Crest past 24 hours: 99 mph
New snowfall at 8,200 feet past 24 hours: 0 to trace inches
Total snow depth at 8,200 feet: 78 inches

Mountain Weather Forecast For Today:
Sunny skies with decreasing winds.
Temperature forecast for 8,000 to 9,000 feet: 31 to 37 deg. F
Ridgetop winds forecast for the Sierra Crest: West at 20 to 30 mph with gusts to 45 mph. Winds shifting to southwest at 10 to 15 mph with gusts to 25 mph in the afternoon.
Snowfall expected in the next 24 hours: 0 inches

2 Day Mountain Weather Forecast:

7000 to 8000 Feet:
Today, clear to partly cloudy skies with daytime highs 37 to 43 deg. F. Southwest winds at 10 to 15 mph with gusts to 30 mph in the morning.

Tonight, mostly cloudy skies with overnight lows around 21 deg. F. Southwest winds around 10 mph.

For Friday, mostly cloudy skies with a chance of snow showers in the afternoon. Daytime highs 39 to 45 deg. F. Southwest winds at 15 to 25 mph with gusts to 35 mph. Winds increasing to 25 to 35 mph with gusts to 50 mph in the afternoon.

Above 8000 Feet:
Today, clear to partly cloudy skies with daytime highs 31 to 37 deg. F. West winds at 20 to 30 mph with gusts to 45 mph. Winds shifting to southwest at 10 to 15 mph with gusts to 25 mph in the afternoon.

Tonight, mostly cloudy skies with overnight lows around 20 deg. F. Southwest winds at 10 to 15 mph with gusts to 25 mph in the evening.

For Friday, mostly cloudy skies with a slight chance of snow showers in the afternoon. Daytime highs 33 to 39 deg. F. Southwest winds at 20 to 35 mph with gusts to 50 mph. Winds increasing to 30 to 45 mph with gusts to 70 mph in the afternoon.

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.