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 Friday, March 30th, 2007 at 7:00 am

The bottom line: Near and above treeline, avalanche danger is LOW this morning. On sun exposed SE-S-SW-W slopes steeper than 35 degrees the avalanche danger will rise to MODERATE as daytime warming occurs. Below treeline, avalanche danger is LOW this morning and will increase to MODERATE in sun exposed areas, 35 degrees and steeper as daytime warming occurs.

The high pressure ridge should weaken a little today as a low pressure system moves into the Pacific Northwest. This low will bring some clouds to the area and should cause the wind to shift to the northwest and west for the rest of the weekend. Temperatures should continue to increase today and remain warm into next week. The high pressure ridge is forecasted to regain strength by Monday and should promote warm, dry weather.

Snow depth at the 8200' Snotel sensor has decreased by about 8 inches over the last two days. This rapid decrease is partly settlement and consolidation of the storm snow and partly melting. As this process happens bonds between layers in the new snow gain strength as does the bond between the new snow and the old snow surface. Yesterday reports of compression and shear failures that required moderate to hard force confirmed this trend. The copious amounts of solar radiation, warm weather, freezing temperatures overnight, and a decrease in the winds should allow the new snow to quickly go through enough melt-freeze cycles to be assimilated into the springtime snowpack and become part of the corn cycle. Over time this process will lead to an increase in stability; however, until the storm snow completely changes over to melt-freeze snow expect to see wet snow instabilities forming on sun exposed slopes. Rollerballs, pinwheels, and loose wet snow slides are all possible on aspects with slopes steeper than 35 degrees that receive lots of sun today. Human triggered slabs are also possible in these areas today. The new snow that has been deposited in cross loaded SE-S aspects and windloaded SW-W aspects will be most prone to warming instability today. However, any areas that are protected from NE-E winds and receive large amounts of solar radiation will be suspect.

Over the last 2 days a breakable sun crust has formed on the snow surface in areas that are exposed to the sun up to 9000'. The surface snow was wet and sticky by mid-day in most areas yesterday. The exception was on N-NW aspects with enough tree cover to prevent much solar radiation from reaching the surface. Good unconsolidated snow still existed in those areas. The E aspects that were scoured back to the old surface should also begin to soften as the day warms up and could provide some good riding conditions. Remember to continually evaluate the conditions as they change over the course of the day and be willing to change plans accordingly.

The bottom line: Near and above treeline, avalanche danger is LOW this morning. On sun exposed SE-S-SW-W slopes steeper than 35 degrees the avalanche danger will rise to MODERATE as daytime warming occurs. Below treeline, avalanche danger is LOW this morning and will increase to MODERATE in sun exposed areas, 35 degrees and steeper as daytime warming occurs.

The Heavenly Ski Patrol has been generous enough to include the Sierra Avalanche Center as one of the benefactors of their annual fundraising party this year. The party is next Friday, April 6th from 7pm to midnight and tickets are $10. A portion of the proceeds will go to SAC. For more information please click here. We also will be raffling off a BCA backpack, beacon, shovel, and probe on April 17th as a way to say thanks to everyone who has sent us a donation in the mail or via Pay Pal. To be entered in this drawing all you have to do is donate $10 or more to SAC. Thanks to all our sponsers, the ski days, and everyone who has donated this season 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.

Andy Anderson, Avalanche Forecaster
Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet):
32 deg. F
Max. temperature at Sierra Crest past 24 hours:
48 deg. F
Average wind direction at Sierra Crest past 24 hours:
Easterly
Average wind speed at Sierra Crest past 24 hours:
30 mph
Maximum wind gust at Sierra Crest past 24 hours:
60 mph
New snow fall at 8,200 feet past 24 hours:
0 inches
Total snow depth at 8,200 feet:
70 inches
Mountain Weather Forecast For Today:
Mostly sunny skies.
Temperature forecast for 8,000 to 9,000 feet:
40 to 49 degrees F.
Ridgetop winds forecast for the Sierra Crest:
Easterly at 20-30 mph shifting to the west northwest at 15-20 mph by this afternoon.
Snowfall expected in the next 24 hours:
0 inches
2 Day Mountain Weather Forecast:

7000 to 8000 Feet:
Today, mostly sunny skies with daytime highs 46 to 54 degrees F and light west northwesterly winds. Tonight, Partly cloudy skies with overnight lows 31 to 37 degrees F and light west winds. Tomorrow, partly cloudy with daytime highs 47 to 53 degrees F. West winds at 10 to 15 mph with gusts to 25 mph.

Above 8000 Feet:
Today, mostly sunny skies with daytime highs 41 to 49 degrees F. Northwest winds at 15 to 20 mph by this afternoon. Tonight, partly cloudy skies with overnight lows around 34 degrees F. West winds at 15 to 20 mph with gusts to 55 mph after midnight. Tomorrow, partly cloudy with daytime highs 41 to 47 degrees F. West winds at 15 to 20 mph with gusts to 40 mph.

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:
	Friday:	Friday Night:	Saturday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.
For 8000-9000 ft:
	Friday:	Friday Night:	Saturday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.