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 13, 2009:


October 13, 2009 at 7:08 am

Fall Avalanche Statement


Forecast Discussion:


With the approach of winter, new snow accumulation in the mid and upper elevations of the Sierra signals the possibility of avalanche activity. Don't let the conditions take you by surprise. Be observant, and use caution if venturing into the backcountry. More variable, complex, and subtle avalanche conditions exist during the early season, making this time of year unexpectedly dangerous. The snowpack does not need to be deep for an avalanche to occur. If the decision is made to travel over snow covered areas, use all of the same care as is required mid winter. Each person should travel with avalanche rescue equipment including a beacon, 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.

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. This includes recent avalanche activity, wind loading, collapse, audible whumpfing sounds, shooting cracks, and/or test slope failure.

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 before the season really gets started. Now is the time to put fresh batteries in avalanche transceivers and practice rescue skills. Check out the avalanche tutorials specifically designed for skiers and snowmobilers at the Forest Service National Avalanche Center web site. Surf through the non-technical glossary found on our links page. Both are worth checking out.

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.


The bottom line:

Fall Avalanche Statement


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:

  Tuesday: Tuesday Night: Wednesday:
Weather:
Temperatures: deg. F. deg. F. deg. F.
Wind direction:
Wind speed:
Expected snowfall: O in. O in. O in.

For 8000-9000 ft:

  Tuesday: Tuesday Night: Wednesday:
Weather:
Temperatures: deg. F. deg. F. deg. F.
Wind direction:
Wind speed:
Expected snowfall: O in. O in. O in.