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 Avalanche Advisory was published on March 7, 2007:


March 7, 2007 at 1:00 am

Forecast Discussion:


This advisory was posted on Wednesday, March 7th, 2007 at 7:00 am

The bottom line: Avalanche danger is LOW for all elevations and aspects. Some isolated, shallow, small windslabs may form on the N-NE aspects near and above treeline by this afternoon. These slabs are not expected to present a hazard to backcountry travelers today. Normal caution is advised for traveling in the backcountry.

There is another weak storm system crossing the forecast area today. It does not have very much moisture associated with it and should only provide some small isolated snow showers. Following this small system a warm high pressure ridge should settle over the area through the weekend bringing continued warm temperatures. The winds have increased as the small disturbance moves in and are expected to remain moderate with some strong gusts from the southwest through tomorrow.

The consistent warm temperatures have allowed melt freeze conditions to become widespread. There is a well formed breakable melt freeze crust on most aspects reaching into the 8000' range. On the southerly aspects these conditions extend all the way up into the 9000' range. With cloud cover and slightly cooler temperatures forecasted today, it should take longer for these crusts to soften. The snowpack is continuing to gain strength as is evidenced by increasing amounts of force required to cause a failure during layer bonding tests as well as most of the overall observations on the snowpack. As the winds increase today, some wind transport of snow may start to occur. There should not be much snow available for transport due to the melt freeze conditions and the good consolidation that has taken place in the snowpack over the last few days. Any windslabs that do form should be shallow, small, and isolated in extent.

The best riding conditions should continue to be found on the upper elevation north-facing, tree-covered slopes. The snow on these slopes is getting heavier, but they still hold some areas of nice, consistent soft snow.

Significant human triggered avalanches are unlikely today. Any avalanche activity is expected to be very small. Natural avalanches are also unlikely.

The bottom line: Avalanche danger is LOW for all elevations and aspects. Some isolated, shallow, small windslabs may form on the N-NE aspects near and above treeline by this afternoon. These slabs are not expected to present a hazard to backcountry travelers today. Normal caution is advised for traveling in the backcountry.

At this time, we are still short $3,000 in funding for our operating budget this winter. If you use this service with any regularity and would like to continue to do so, please show your financial support for the Sierra Avalanche Center. You may make a tax deductible donation directly to us via Paypal or by sending a check to our address listed above, c/o the Truckee Ranger Station. A graph showing the amount of fundraising completed this season and our overall budget is available by clicking here. The financial support already received this winter from a variety of users is greatly appreciated.

Andy Anderson , Avalanche Forecaster
Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet):
29 deg. F
Max. temperature at Sierra Crest past 24 hours:
44 deg. F
Average wind direction at Sierra Crest past 24 hours:
Southwesterly
Average wind speed at Sierra Crest past 24 hours:
20-25 mph
Maximum wind gust at Sierra Crest past 24 hours:
43 mph
New snow fall at 8,200 feet past 24 hours:
0 inches
Total snow depth at 8,200 feet:
91 inches
Mountain Weather Forecast For Today:
Mostly cloudy with some isolated snow showers.
Temperature forecast for 8,000 to 9,000 feet:
32 to 42 degrees F.
Ridgetop winds forecast for the Sierra Crest:
Southwesterly 20-35 mph, gusting to 60 mph.
Snowfall expected in the next 24 hours:
Trace
2 Day Mountain Weather Forecast:

7000 to 8000 Feet
Today, mostly cloudy with some isolated snow showers. Daytime highs 42 to 48 degrees F. Southwest winds at 15 to 25 mph with gusts to 35 mph in the afternoon. Tonight, partly cloudy then clearing after midnight. Overnight lows around 23 degrees F. Southwest winds at 15 to 25 mph with gusts to 35 mph. Thursday, partly cloudy with daytime highs 43 to 49 degrees F. Southwest winds at 10 to 20 mph with gusts to 30 mph.

Above 8000 Feet
Today, mostly cloudy with some isolated snow showers. Daytime highs 32 to 42 degrees F. Southwest winds at 20 to 35 mph with gusts to 60 mph in the afternoon. Tonight, partly cloudy then clearing after midnight. Overnight lows 20 to 28 degrees F. Southwest winds at 10 to 20 mph with gusts to 55 mph. Thursday, partly cloudy with daytime highs 33 to 41 degrees F. Southwest winds at 10 to 20 mph with gusts to 50 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:

  Wednesday: Wednesday Night: Thursday:
Weather:
Temperatures: deg. F. deg. F. deg. F.
Wind direction:
Wind speed:
Expected snowfall: O in. O in. O in.

For 8000-9000 ft:

  Wednesday: Wednesday Night: Thursday:
Weather:
Temperatures: deg. F. deg. F. deg. F.
Wind direction:
Wind speed:
Expected snowfall: O in. O in. O in.