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 November 8, 2012:

November 8, 2012 at 9:04 am

Early season conditions update #4

We do not have enough information to issue regular avalanche advisories. We have started to collect data and will be sharing all of the information we gather on our observations page and in intermittent updates to this page. We plan to resume daily avalanche advisories in November as conditions dictate.

Forecast Discussion:

We are still working with very limited observations and resources during this early season period. Very limited observations over the past few days have revealed a stable snowpack that is in good condition to handle new snow loading. Overall, very little snow exists on south and west aspects. North and northeast aspects hold a snowpack generally 1 to 3 feet deep at the mid and upper elevations. Old snow surface conditions are generally a mix of rain crust, melt freeze crust, and dense wind pack. Isolated pockets of unconsolidated snow exist in areas of full shade at the upper elevations. 

A cold storm system will bring new snowfall to the forecast area Thursday and Friday with 6 to 12 inches of new snow expected above 7,000'. Cold air temperatures and snow showers are expected to linger through the weekend. Old snow on the ground appears in a stable state. Snowpack instability and any avalanche activity over the next few days is expected to involve only new snow and occur at or above the old/new snow interface. The vast majority of instability associated with this storm cycle is expected to occur in wind loaded areas. Human triggered wind slab avalanches will be possible over the next few days. Please check the observations page for snowpack updates associated with this storm cycle.

When traveling in the backcountry continue to make constant observations and look for indications of current or recent snowpack instability. The best indicator is recent avalanche activity. Wind loading, collapse, audible whumpfing sounds, shooting cracks, and/or test slope failure also represent excellent indications that an unstable snowpack exists in the immediate area. Once an unstable snowpack has formed, the only additional ingredients to create an avalanche are a slope steeper than 30 degrees and a trigger.

If you plan to embark on some early season adventures in 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. Keep in mind the many hazards such as rocks, down trees, and stumps that lie hidden just beneath the snow surface. An injury at this time of year can make for a very long winter. Getting out and practicing companion rescue skills remains one of the best activities at this time.

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.


The bottom line:

Early season conditions update #4

We do not have enough information to issue regular avalanche advisories. We have started to collect data and will be sharing all of the information we gather on our observations page and in intermittent updates to this page. We plan to resume daily avalanche advisories in November as conditions dictate.


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:
  Thursday: Thursday Night: Friday:
Weather:
Temperatures: deg. F. deg. F. deg. F.
Wind direction:
Wind speed:
Expected snowfall: O in. O in. O in.

For 8000-9000 ft:
  Thursday: Thursday Night: Friday:
Weather:
Temperatures: deg. F. deg. F. deg. F.
Wind direction:
Wind speed:
Expected snowfall: O in. O in. O in.