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 3, 2007:


March 3, 2007 at 1:00 am

Forecast Discussion:


This advisory was posted on Saturday, March 3rd, 2007 at 6:56 am

The bottom line: Near and above treeline, avalanche danger is MODERATE on wind loaded SW-W-NW aspects 35 degrees and steeper. Avalanche danger is LOW on N-NE-E aspects near and above treeline. Below treeline, avalanche danger is LOW.

High pressure will dominate the forecast area today and provide clear skies. Ridgetop winds have remained easterly overnight and are expected to continue through the day today. Maximum daytime air temperatures are expected to increase again today, with noticeable warming at the upper elevations. The high pressure is expected to move quickly to the east today as a weak weather system moves in off the Pacific Ocean overnight, increasing cloud cover over the area on Sunday.

The storm snow from the past week has settled and stabilized well. An additional 3 inches of settlement was observed in the past 24 hours at 8,200'. Gradually warming air temperatures over the past two days have contributed to stabilization of the recent storm snow.

Yesterday, moderate easterly ridgetop winds caused wind loading on SW-W-NW aspects. The snow above treeline was already wind affected from the recent storm and was able to form shallow, cohesive slabs very quickly. These new wind slabs will remain active today as east winds continue this morning. Warming air temperatures may make these slabs more sensitive today, especially on SW-W aspects above treeline.

Easterly ridgetop winds have scoured avalanche start zones on N-NE-E aspects above treeline, especially along the Sierra Crest. Significant east winds did not start in the Mount Rose are until late yesterday. This has removed the snow that caused lingering surface instability on Thursday on N-NE-E aspects, and has further stabilized the snowpack. Avalanche activity is unlikely today in these wind scoured start zones.

Human triggered avalanches are possible today near and above treeline on wind loaded SW-W-NW aspects, 35 degrees and steeper. Natural avalanches are unlikely. These shallow slabs are relatively small at around 1 foot deep. There is still enough snow involved to bury, injure, or kill a person, especially in larger avalanche paths. Backcountry travelers should exercise caution today while traveling in these areas.

The bottom line: Near and above treeline, avalanche danger is MODERATE on wind loaded SW-W-NW aspects 35 degrees and steeper. Avalanche danger is LOW on N-NE-E aspects near and above treeline. Below treeline, avalanche danger is LOW.

At this time, we are still short $4,000 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.

Brandon Schwartz, Avalanche Forecaster

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Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet): 20 deg. F
Max. temperature at Sierra Crest past 24 hours: 31 deg. F
Average wind direction at Sierra Crest past 24 hours: Easterly
Average wind speed at Sierra Crest past 24 hours: 35 mph
Maximum wind gust at Sierra Crest past 24 hours: 67 mph
New snow fall at 8,200 feet past 24 hours: 0 inches
Total snow depth at 8,200 feet: 102 inches

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Mountain Weather Forecast For Today:
Clear skies.
Temperature forecast for 8,000 to 9,000 feet: 34 to 40 degrees F.
Ridgetop winds forecast for the Sierra Crest: Easterly 30-45 mph, gusting to 60 mph, decreasing in the afternoon.
Snowfall expected in the next 24 hours: 0 inches

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2 Day Mountain Weather Forecast:
7000 to 8000 Feet
Today, sunny skies with daytime highs 39 to 45 degrees F. East winds at 10 to 15 mph. Tonight, partly cloudy with overnight lows 21 to 31 degrees F. Southeast winds at 10 to 20 mph. Sunday, mostly cloudy with daytime highs around 44 degrees F. Southwest winds at 10 to 15 mph are expected.

Above 8000 Feet
Today, sunny skies with daytime highs 34 to 40 degrees F. East winds at 30 to 45 mph with gusts to 60 mph in the morning. East winds decreasing to 10 to 20 mph in the afternoon. Tonight, partly cloudy with overnight lows 25 to 31 degrees F. South winds at 10 to 20 mph. Sunday, mostly cloudy with daytime highs 35 to 41 degrees F. Southwest winds at 15 to 25 mph with gusts to 35 mph are expected.


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:

  Saturday: Saturday Night: Sunday:
Weather:
Temperatures: deg. F. deg. F. deg. F.
Wind direction:
Wind speed:
Expected snowfall: O in. O in. O in.

For 8000-9000 ft:

  Saturday: Saturday Night: Sunday:
Weather:
Temperatures: deg. F. deg. F. deg. F.
Wind direction:
Wind speed:
Expected snowfall: O in. O in. O in.