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 Monday, April 16th, 2007 at 7:00 am

The bottom line: Near and above treeline the avalanche danger is MODERATE on recently wind loaded NW-W and on cross loaded SE aspects, 35 degrees and steeper. As daytime warming occurs wet snow instabilities should start to form on the sun exposed aspects. Below treeline, avalanche danger is LOW.

A short lived high pressure ridge moving over the forecast area today should bring warmer temperatures and clear skies. The east northeast winds should continue through today. Another small disturbance is forecasted to move to the north of the area on Tuesday causing the winds to increase and shift back to the southwest. It should also bring temperatures well below normal. However, little or no moisture is associated with this next system. This pattern of alternating warmer, dry high pressure and small, cold low pressure systems that produce small bursts of snow is forecasted to continue through the week.

The northeast winds have scoured most of N-NE-E aspects down to the old hard melt-freeze crust and redepositted the newly fallen snow onto the NW-W-SW-S-SE aspects. Today the significant jump in air temperatures and clear sunny skies will expose these newly formed windslabs and the new snow that exists across the forecast area to rapid warming. As daytime warming occurs today, wet snow instabilities should start to form on the sun exposed aspects. Cross loaded SE aspects where new snow sits on top of an old snow bed surface will be the most likely locations for any snowpack instability today. Over the last few weeks the snowpack on many of the S-SW-W aspects has melted so much that new snow has been transported onto bare ground. No significant snowpack instability is expected in these areas due to the presence of excellent anchoring.

Natural avalanche activity is unlikely but not impossible today on SE aspects. Naturally occurring snowpack instability is expected to be limited to roller ball activity on all sun exposed slopes, as snow melts off of rocks and trees. Human triggering of small slab avalanches on wind loaded slopes that are exposed to the sun is possible today. Humans could also trigger loose point-release sluffs, pinwheels, and rollerballs as the day warms up.

The bottom line: Near and above treeline the avalanche danger is MODERATE on recently wind loaded NW-W and on cross loaded SE aspects, 35 degrees and steeper. As daytime warming occurs wet snow instabilities should start to form on the sun exposed aspects. Below treeline, avalanche danger is LOW.

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.

Andy Anderson , Avalanche Forecaster
Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet):
23 deg. F
Max. temperature at Sierra Crest past 24 hours:
33 deg. F
Average wind direction at Sierra Crest past 24 hours:
East northeasterly
Average wind speed at Sierra Crest past 24 hours:
35 - 40 mph
Maximum wind gust at Sierra Crest past 24 hours:
83 mph
New snow fall at 8,200 feet past 24 hours:
Trace
Total snow depth at 8,200 feet:
56 inches
Mountain Weather Forecast For Today:
Sunny and warmer .
Temperature forecast for 8,000 to 9,000 feet:
43 - 49 degrees F.
Ridgetop winds forecast for the Sierra Crest:
Northeasterly 30 - 40 mph, gusting to 70 mph
Snowfall expected in the next 24 hours:
0 inches
2 Day Mountain Weather Forecast:

7000 to 8000 Feet:
Today, sunny skies with daytime highs 48 to 54 degrees F. East winds at 10 to 20 mph. Tonight, partly cloudy skies with overnight lows around 30 degrees F. West winds at 10 to 20 mph. Tuesday, mostly cloudy skies with a slight chance of snow showers. Daytime highs 43 to 49 degrees F. Southwest winds at 20 to 30 mph increasing to 30 to 40 mph with gusts to 50 mph in the afternoon.

Above 8000 Feet:
Today, sunny skies with daytime highs 43 to 49 degrees F. Northeast winds at 30 to 40 mph with gusts to 70 mph. Tonight, partly cloudy skies with overnight lows around 28 degrees F. Northwest winds at 10 to 15 mph shifting to west winds at 15 to 25 mph after midnight. Tuesday, mostly cloudy skies with a slight chance of snow showers. Daytime highs 37 to 43 degrees F. West winds at 25 to 40 mph with gusts to 80 mph shifting to southwest winds at 35 to 45 mph with gusts to 90 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:
	Monday:	Monday Night:	Tuesday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.
For 8000-9000 ft:
	Monday:	Monday Night:	Tuesday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.