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 October 21, 2012:


October 21, 2012 at 11:21 am

Fall Avalanche Statement 

Daily avalanche advisories are planned to resume in mid November or later as conditions dictate. Occasional intermittent early season updates to this page may occur earlier if conditions warrant and resources are available.


Forecast Discussion:


The first storm cycle of the season is lined up for this week. New snowfall amounts of 1 to 3 feet are possible over the upper elevations. Expect accumulating snowfall Sunday night through Thursday. Mellow touring over snow covered forest roads will certainly be an option this week. More recreation opportunities might exist if upper end forecast snowfall amounts are reached.

With little (if any) exception, new snow this week will deposit onto bare ground. This will keep snowpack instability and avalanche concerns limited to within the storm snow and to wind slabs that form on wind loaded slopes. Areas directly below ridgelines as well as gully features that are subject to wind loading may exhibit slab formation despite a shallow snowpack. Wind loading can increase snow deposition rates by 2 to 10 times the rate that snow is falling from the sky. This rapid loading can create enough snowpack instability for an avalanche to occur, despite only a few inches of snow on the ground in wind protected areas. Make constant observations as you travel, looking for indications of current or recent snowpack instability. The best indicator is recent avalanche activity. Other signs of snowpack instability including wind loading, collapse, audible whumpfing sounds, shooting cracks, and/or test slope failure are excellent indications that the snowpack in the immediate area is unstable. All that is needed is a slope steeper than 30 degrees and a trigger.

If headed out to travel on or near avalanche terrain, each person should travel with avalanche rescue equipment including a transceiver, probe, and shovel with which they are well practiced. Allow only one person at a time to travel on slopes that are steeper than 30 degrees. Many hazards such as rocks, down trees, and stumps are often hidden just beneath the snow surface. Travel cautiously and slowly as it is a very long winter after getting hurt this time of year. Often the best way to satiate early season excitement is to put fresh batteries in avalanche transceivers and practice rescue skills while out touring on snow covered forest roads.

Check out the avalanche tutorials specifically designed for skiers and snowmobilers at the Forest Service National Avalanche Center web site.

Current remote weather station data from the NWS can be found by clicking here. A general weather forecast for the area can be found by clicking here.

Please note: If you are intending to travel within the boundaries of a ski area that is not yet open for the season, no avalanche mitigation measures exist at this time. Please treat any closed ski area as the backcountry terrain and snowpack that it currently is. Respect any closure signs that may be in place at the parking lot or base area. Carry proper backcountry equipment and avalanche rescue equipment. Expose only one person at a time to avalanche terrain (which is often widespread and complex within a ski area). Do not traverse above others. Things may look the same and seem very familiar to an operating ski area, but from a safety standpoint, right now the risk is significantly higher.


The bottom line:

Fall Avalanche Statement 

Daily avalanche advisories are planned to resume in mid November or later as conditions dictate. Occasional intermittent early season updates to this page may occur earlier if conditions warrant and resources are available.


Brandon Schwartz - Avalanche Forecaster, Tahoe National Forest


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

0600 temperature: deg. F.
Max. temperature in the last 24 hours: deg. F.
Average wind direction during the last 24 hours:
Average wind speed during the last 24 hours: mph
Maximum wind gust in the last 24 hours: mph
New snowfall in the last 24 hours: O inches
Total snow depth: inches

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

For 7000-8000 ft:

  Sunday: Sunday Night: Monday:
Weather:
Temperatures: deg. F. deg. F. deg. F.
Wind direction:
Wind speed:
Expected snowfall: O in. O in. O in.

For 8000-9000 ft:

  Sunday: Sunday Night: Monday:
Weather:
Temperatures: deg. F. deg. F. deg. F.
Wind direction:
Wind speed:
Expected snowfall: O in. O in. O in.