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 February 9, 2011:


February 9, 2011 at 7:56 am

The avalanche danger remains LOW for all elevations and aspects. Please use normal caution while traveling in the backcountry.


Forecast Discussion:


The forecast calls for a mostly sunny but cold day today with daytime highs only forecasted to reach into the mid 20's above 7000 ft. The east winds should continue today as well. By this evening these winds should start to decrease as a high pressure ridge builds over the forecast area. This ridge should allow temperatures to start warming back up over the next few days.

Observations:

A mix of surface crusts, wind scoured surfaces, and some areas of softer snow comprises the snow surface across the forecast area. On Echo Peak yesterday, the N-NE aspects held a thin, breakable crust, while mostly firm melt-freeze conditions existed on the more sun exposed aspects. Some shallow (about 1 inch), short-lived softening did occur on S-SW aspects by mid afternoon. Farther north in Ward Canyon (photos and video) and on Lincoln Ridge strong winds had scoured the  exposed N-NE-E aspects near and above treeline leaving behind firm crusts. The solar aspects in these areas held firm melt-freeze crusts that showed no signs of softening due to more widespread, longer-lasting cloud cover. On the more sheltered N aspects in these areas, about 3-6 inches of softer snow remained. On Lincoln Ridge a thin, breakable crust similar to the ones on Echo Peak existed up to 7400 ft on the N-NE-E aspects. Stability tests and general observations in all three of these areas showed a mostly stable snowpack.

Avalanche Concerns:

Avalanche activity will remain unlikely today. The snowpack continues to gain strength and shows very few if any signs of lingering instabilities. Due to the lack of snow available for transport, no new wind loading has occurred for several days even though several strong wind events have happened. With temperatures forecasted to remain well below freezing today, not enough melting will occur for wet snow instabilities to form. Any instabilities that do exist in the forecast area should remain extremely isolated. Even though avalanches remain unlikely, they are not impossible. Continue to evaluate slopes carefully before committing to them and travel with caution in the backcountry.


The bottom line:

The avalanche danger remains LOW for all elevations and aspects. Please use normal caution while traveling in the backcountry.


Andy Anderson - Avalanche Forecaster, Tahoe National Forest


Weather Observations from along the Sierra Crest between 8200 ft and 8800 ft:

0600 temperature: 11-13 deg. F.
Max. temperature in the last 24 hours: 15-22 deg. F.
Average wind direction during the last 24 hours: East
Average wind speed during the last 24 hours: 35-45 mph
Maximum wind gust in the last 24 hours: 82 mph
New snowfall in the last 24 hours: O inches
Total snow depth: 59-86 inches

Two-Day Mountain Weather Forecast - Produced in partnership with the Reno NWS

For 7000-8000 ft:

  Wednesday: Wednesday Night: Thursday:
Weather: Sunny Clear Sunny
Temperatures: 24-31 deg. F. 14-22 deg. F. 35-42 deg. F.
Wind direction: East East East
Wind speed: 10 mph with gusts to 30 mph 10-15 mph with gusts to 30 mph 10 mph with gusts to 25 mph becoming light in the afternoon
Expected snowfall: O in. O in. O in.

For 8000-9000 ft:

  Wednesday: Wednesday Night: Thursday:
Weather: Sunny Clear Sunny
Temperatures: 20-27 deg. F. 20-26 deg. F. 31-38 deg. F.
Wind direction: East East East
Wind speed: 20-30 mph with gusts to 50 mph decreasing to 40 mph in the afternoon 20-30 mph with gusts to 40 mph decreasing to 15-20 mph with gusts to 30 mph after midnight 10-15 mph with gusts to 25 mph
Expected snowfall: O in. O in. O in.