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 11, 2008 7:00 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 avalanche danger will develop on slopes steeper than 37 degrees on all aspects below 7500 ft and on E-SE-S-SW-W aspects above 7500 ft in response to daytime warming.

A strong high pressure, light winds and some overnight cloud cover kept temperatures above freezing at the higher elevations till 1am last night. Below 7500' some areas did not drop below freezing. The forecast calls for another day with warmer than normal temperatures and light winds. Skies should be mostly clear today until clouds start to move in from the north this afternoon. This cloud cover should mainly affect the areas north of Highway 50. Winds and cloud cover should start to increase tonight and tomorrow as a series of low pressure systems begins to move into the area.

Observations yesterday indicate that the spring sun and warm air temperatures are melting some low elevation northerly aspects enough to create wet snow instabilities. Human triggered large pinwheels (up to 4ft in diameter) and small (D1) point release slides occurred on steep N-NE aspects in the Deep Creek area yesterday afternoon below 7500 ft. Observers also reported wet, heavy snow on all aspects below 7000 ft by noon yesterday on Jake's peak. Recently, observations from Castle Peak, Deep Creek, Mt. Tallac, Rose Knob Peak, and Jake's Peak show that 2 to 4 inches of soft corn snow forms by midday on southerly aspects. Later in the day these slopes get softer, wetter, and less stable as the balance between strong refrozen snow and wet, weak melting snow tips toward the melting snow. Overnight radiational cooling and air temperatures near or below freezing continue to swing this balance back to the freezing side and the snow that melted during the day refreezes and gains strength.

Today, warm air temperatures and more spring time sun will cause free water to form in the snowpack due to melting. This free water will weaken the snowpack and wet snow instabilities could form on steep sun exposed slopes as daytime warming occurs. Increased cloud cover north of Highway 50 should limit some of these wet snow instabilities if it develops by early afternoon. A more robust overnight refreeze due to cooler temperatures and radiational cooling, the extended duration of this melt/freeze cycle, and slightly cooler temperatures should help prevent wet snow instabilities from becoming large and widespread today. Human triggered avalanches will still become possible this afternoon. Natural avalanches are unlikely today.

The bottom line: This morning, avalanche danger is LOW for all elevations and aspects. Areas of MODERATE avalanche danger will develop on slopes steeper than 37 degrees on all aspects below 7500 ft and on E-SE-S-SW-W aspects above 7500 ft 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.

Andy Anderson, Avalanche Forecaster

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: 47 deg. F.
Average wind direction at Sierra Crest past 24 hours: Southwest
Average wind speed at Sierra Crest past 24 hours: 25 mph.
Maximum wind gust at Sierra Crest past 24 hours: 49 mph
New snowfall at 8,200 feet past 24 hours: 0 inches
Total snow depth at 8,200 feet: 79 inches
Mountain Weather Forecast For Today:
Mostly clear this morning with clouds moving in from the north this afternoon.
Temperature forecast for 8,000 to 9,000 feet: 40 to 45 deg. F
Ridgetop winds forecast for the Sierra Crest: West at 15 to 25 mph with gusts to 40 mph decreasing to 10 to 20 mph with gusts to 30 mph this afternoon.
Snowfall expected in the next 24 hours: 0 inches
2 Day Mountain Weather Forecast:

7000 to 8000 Feet:
Today, partly cloudy skies in the morning, mostly cloudy skies in the afternoon. Daytime highs 43 to 51 deg. F. Light winds becoming west at 10 to 15 mph with gusts to 25 mph in the afternoon.

Tonight, partly cloudy skies with overnight lows 30 to 35 deg. F. West winds at 10 mph.

For Wednesday, mostly cloudy skies with daytime highs 41 to 49 deg. F. West winds at 10 to 20 mph with gusts to 35 mph in the afternoon.

Above 8000 Feet:
Today, partly cloudy skies in the morning, mostly cloudy skies in the afternoon. Daytime highs 40 to 45 deg. F. West winds at 15 to 25 mph with gusts to 40 mph decreasing to 10 to 20 mph with gusts to 30 mph this afternoon.

Tonight, partly cloudy skies with overnight lows 30 to 35 deg. F. West winds at 10 to 20 mph.

For Wednesday, mostly cloudy skies with daytime highs 38 to 43 deg. F. West winds at 15 to 25 mph with gusts to 35 mph increasing to 20 to 35 mph with gusts to 60 mph 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:
	Tuesday:	Tuesday Night:	Wednesday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.
For 8000-9000 ft:
	Tuesday:	Tuesday Night:	Wednesday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.