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 January 30, 2013:

January 30, 2013 at 7:45 am

Avalanche danger is LOW for all elevations and aspects. Normal caution is advised. In some above treeline areas, surface rain crusts are smooth, hard, and difficult to travel. Long sliding falls may be difficult to self arrest.

Forecast Discussion:

High pressure continues to build over the forecast area. Cloud cover that lingered yesterday over the northern half of the forecast area will give way to sunny skies across the region today. Ridgetop wind speed decreased overnight. Winds are expected out of the NE today at light to moderate in speed. Air temperatures above 8,000' are in the upper 20s to low 30s this morning. Air temperatures are forecast to warm above freezing today for all elevations.

Recent Observations:

Observations made yesterday on Rubicon Peak (West Shore Tahoe area) and on Mt. Ralston (Echo Summit area) revealed very small wind slabs in isolated areas. These very small slabs existed near ridgelines in near and above treeline terrain mainly on SE-S-SW-W aspects. Isolated wind slabs have also been observed on N aspects in areas not fully scoured by recent N-NE winds. All wind slabs observed over the past two days have been very small extending only a few feet down slope from the ridgetop. Minor amounts of wet surface snow were observed yesterday below 8,000' in sun exposed areas (photos, pit profiles, videos, more info). None of the observed instability over the past two days has involved enough snow to significantly injure or bury a person.

Avalanche Problems: Avalanches involving sufficient snow to significantly injure or bury a person are expected to be very isolated at most today.

Daytime warming, decreased winds, and air temperatures well above freezing will allow for some minor wet snow instability to form today. Small, mainly human triggered loose wet snow avalanches are possible today on SE-S-SW aspects on slopes 37 degrees and steeper. The expected amount of wet snow involved is small, but undesirable interaction with secondary terrain features such as cliffs and terrain traps will increase the hazard.

Any lingering unstable wind slabs are expected to be very small and shallow. They will be found just below ridgelines in near and above treeline terrain on a variety of aspects. Again insufficient snow involvement to create significant injury or burial is expected. Undesirable interaction with secondary terrain features such as cliffs and terrain traps will increase the hazard.


The bottom line:

Avalanche danger is LOW for all elevations and aspects. Normal caution is advised. In some above treeline areas, surface rain crusts are smooth, hard, and difficult to travel. Long sliding falls may be difficult to self arrest.


Brandon Schwartz - Avalanche Forecaster, Tahoe National Forest

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

0600 temperature: 26 to 31 deg. F.
Max. temperature in the last 24 hours: 30 to 38 deg. F.
Average wind direction during the last 24 hours: Northeast
Average wind speed during the last 24 hours: 33 mph
Maximum wind gust in the last 24 hours: 78 mph
New snowfall in the last 24 hours: O inches
Total snow depth: 57 to 83 inches

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

For 7000-8000 ft:
  Wednesday: Wednesday Night: Thursday:
Weather: Sunny skies. Clear skies. Sunny skies.
Temperatures: 40 to 45 deg. F. 28 to 33 deg. F. 44 to 49 deg. F.
Wind direction: NE to E E E
Wind speed: 5 to 15 mph. 5 to 15 mph. 5 to 15 mph in the morning, becoming light.
Expected snowfall: O in. O in. O in.

For 8000-9000 ft:
  Wednesday: Wednesday Night: Thursday:
Weather: Sunny skies. Clear skies. Sunny skies.
Temperatures: 35 to 40 deg. F. 27 to 33 deg. F. 38 to 44 deg. F.
Wind direction: N NE NE shifting to NW
Wind speed: 15 to 20 mph with gusts to 30 mph. 15 to 25 mph with gusts to 35 mph. 10 to 15 mph. Gusts to 25 mph in the morning.
Expected snowfall: O in. O in. O in.