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 12, 2009:


January 12, 2009 at 7:56 am

The avalanche danger is LOW for all elevations and aspects. Use normal caution.


Forecast Discussion:


Sunny, warm, and windy weather will continue over the forecast area. Daytime highs should reach into the upper 40's and low 50's again today. Last night overnight lows dropped into the upper 20's and low 30's. They should do the same tonight. Cool east to northeast winds should continue today. These winds should be stronger during the day and start to decrease tonight. This sunny, dry, and breezy weather pattern should continue until the high pressure starts to move east later this week.

Observations near Carson Pass, on Castle Peak, on Mt. Judah, and in the Mt. Rose area continue to show a variety of wind affected snow, melt-freeze snow, supportable crusts, and breakable crusts on the surface in most areas. Only a few small pockets of unconsolidated snow still exist on higher elevation northerly, tree-covered aspects that are protected from wind and sun. Yesterday, some softening occurred on southerly aspects below 8800'. Unfortunately, snow cover on these aspects is limited, and large areas of dirt and rocks are still exposed. The surface snow that melted and softened yesterday refroze quickly by late afternoon. This refreeze should have continued last night due to radiational cooling and below freezing temperatures.

Snowpits continue to reveal pockets of depth hoar in some areas that had snow cover before the December storms. The strength and distribution of this weak layer varies greatly across the forecast area and even across a slope. Right now avalanche activity remains unlikely on this layer due to strong well-bonded snow on top of the depth hoar that should have enough strength to hold itself up. The current weather should allow this weak layer to gain some strength before the next storm cycle.

Today strong, cool northeast winds and the weak January sun will prevent the snow surface from softening and melting very much. These two factors combined with the prolonged melt-freeze cycle should keep wet snow avalanche activity unlikely today. On sun-exposed, southerly aspects below 8800' the top 1-2 inches of surface snow should soften due to daytime warming today. These surfaces will quickly refreeze as soon as they lose direct sun. 


The bottom line:

The avalanche danger is LOW for all elevations and aspects. Use normal caution.


Andy Anderson - Avalanche Forecaster, Tahoe National Forest


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

0600 temperature: 29 deg. F.
Max. temperature in the last 24 hours: 42 deg. F.
Average wind direction during the last 24 hours: Northeast
Average wind speed during the last 24 hours: 35-50 mph
Maximum wind gust in the last 24 hours: 89 mph
New snowfall in the last 24 hours: O inches
Total snow depth: 60 inches

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

For 7000-8000 ft:

  Monday: Monday Night: Tuesday:
Weather: Sunny Clear Sunny
Temperatures: 46-53 deg. F. 28-38 deg. F. 50-57 deg. F.
Wind direction: Northeast East East
Wind speed: 15-25 mph with gusts to 35 mph 10-20 mph with gusts to 30 mph 10-15 mph with gusts to 35 mph
Expected snowfall: O in. O in. O in.

For 8000-9000 ft:

  Monday: Monday Night: Tuesday:
Weather: Sunny Clear Sunny
Temperatures: 43-50 deg. F. 30-40 deg. F. 51-57 deg. F.
Wind direction: Northeast Northeast North
Wind speed: 30-40 mph with gusts to 70 mph decreasing to 20-30 mph with gusts to 50 mph in the afternoon 15-25 mph with gusts to 40 mph 15-25 mph with gusts to 40 mph
Expected snowfall: O in. O in. O in.