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 2, 2009:


February 2, 2009 at 7:47 am

Avalanche danger is LOW for all elevations and aspects. Normal caution is advised.


Forecast Discussion:


Sunny skies and above average air temperatures will continue for the next few days. A well advertised return of precipitation is forecast to occur later this week. An air temperature inversion is in place this morning with most remote sensors above 7,000' reporting air temperatures in the upper 30s to low 40s. Ridgetop winds became calm overnight, but are forecast to increase to light to moderate from the northeast as the day progresses.

General observations and snowpit data from around the forecast area continue to indicate a stable snowpack. Some faceting has been observed within the recent storm snow and around the January 22-23 rain crust. Stability tests are indicating failure of the rain crust layer under moderate to hard force. No evidence of fracture propagation potential has been observed and failure of this layer remains unlikely at his time. Large patches of surface hoar formation have been observed in wind protected open areas, generally at lower elevations. Existing surface hoar will only pose a problem if it manages to persist through Wednesday evening. For today, natural and human triggered avalanche activity remains unlikely.

Snow surface conditions are very dependent on aspect and wind exposure. Above treeline, expect high density wind affected snow surfaces on all aspects. In sun exposed areas, melt-freeze conditions exist, especially in more wind protected areas. Very enjoyable unconsolidated snow surface conditions remain in wind sheltered areas on NW-N-NE aspects.


The bottom line:

Avalanche danger is LOW for all elevations and aspects. Normal caution is advised.


Brandon Schwartz - Avalanche Forecaster, Tahoe National Forest


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

0600 temperature: 36 to 42 deg. F.
Max. temperature in the last 24 hours: 42 to 44 deg. F.
Average wind direction during the last 24 hours: Northeast, becoming calm.
Average wind speed during the last 24 hours: 23 mph prior to 1600, then 2 mph
Maximum wind gust in the last 24 hours: 44 mph
New snowfall in the last 24 hours: O inches
Total snow depth: 67 inches

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

For 7000-8000 ft:

  Monday: Monday Night: Tuesday:
Weather: Sunny skies. Clear skies. Sunny skies.
Temperatures: 46 to 53 deg. F. 25 to 33 deg. F. 46 to 53 deg. F.
Wind direction: NE S S
Wind speed: Less than 10 mph. Around 10 mph. 10 to 15 mph.
Expected snowfall: O in. O in. O in.

For 8000-9000 ft:

  Monday: Monday Night: Tuesday:
Weather: Sunny skies. Clear skies. Sunny skies.
Temperatures: 41 to 48 deg. F. 30 to 36 deg. F. 41 to 48 deg. F.
Wind direction: NE SW SW
Wind speed: 10 to 15 mph with gusts to 25 mph. 10 to 15 mph with gusts to 25 mph. 10 to 15 mph with gusts to 30 mph.
Expected snowfall: O in. O in. O in.