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 29, 2009:


January 29, 2009 at 8:00 am

The avalanche danger is LOW for all elevations and aspects. Use normal caution when travelling in the backcountry.


Forecast Discussion:


A high pressure ridge over the west coast should bring warmer temperatures, clear skies, and continued easterly winds to the forecast area. Today, high temperatures should reach into the low 40's at all elevations. The forecast calls for continued high pressure and springlike weather into next week.

Yesterday, observations and layer-bonding tests from Highland Peak (near Ebbetts Pass), Bear Valley, and Mt. Judah (near Donner Pass) indicated a mostly stable snowpack. Both the bonds within the recent snow and between the older snow surfaces and the recent snow are gaining strength. The easterly winds continued to transport small amounts of snow over the ridgelines. Observations across the forecast area revealed that wind slabs formed by these east winds have remained small and inconsequential. A sun crust formed over the last two days on southerly aspects below 8000'. Several inches of soft, unconsolidated snow exists on protected NW-N-NE-E aspects.

The limited amount of wind-transported snow should prevent large, dangerous wind slabs from forming today. Gradual warming since Monday, cool easterly winds, below freezing temperatures overnight, and the weak January sun should limit wet snow instabilities to pinwheels and small, point-release sluffs on sun exposed southerly aspects steeper than 35 degrees. These warming instabilities could occur naturally or be triggered by a person on the slope. Even though these instabilities should not entrain enough snow to bury a person, they could be large enough to knock a person off-balance. Getting knocked over in the wrong place (the top of a cliff for instance) could have dangerous consequences. Be aware of the surroundings. Use caution and safe travel to minimize risks. Slab avalanche activity will remain unlikely but not impossible today.


The bottom line:

The avalanche danger is LOW for all elevations and aspects. Use normal caution when travelling 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: 22 deg. F.
Max. temperature in the last 24 hours: 31 deg. F.
Average wind direction during the last 24 hours: East northeast
Average wind speed during the last 24 hours: 32 mph
Maximum wind gust in the last 24 hours: 52 mph
New snowfall in the last 24 hours: O inches
Total snow depth: 72 inches

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

For 7000-8000 ft:

  Thursday: Thursday Night: Friday:
Weather: Sunny Clear Sunny
Temperatures: 36-45 deg. F. 20-30 deg. F. 42-49 deg. F.
Wind direction: East East East
Wind speed: 10-15 mph with gusts to 25 mph 10-15 mph 10-15 mph with gusts to 30 mph becoming light in the afternoon
Expected snowfall: O in. O in. O in.

For 8000-9000 ft:

  Thursday: Thursday Night: Friday:
Weather: Sunny Clear Sunny
Temperatures: 38-44 deg. F. 26-32 deg. F. 43-49 deg. F.
Wind direction: East East East
Wind speed: 20-30 mph with gusts to 45 mph 15-25 mph with gusts to 35 mph increasing to gusts to 45 mph after midnight 15-25 mph with gusts to 45 mph decreasing to 10-15 mph in the afternoon
Expected snowfall: O in. O in. O in.