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 December 9, 2006:

December 9, 2006 at 1:00 am

Forecast Discussion:

This advisory was posted on Saturday, December 9, 2006 at 6:52 am

Our SAC Ski Day tickets are now available. This is an excellent opportunity for you to make a donation to SAC by purchasing a heavily discounted lift ticket that was donated to us by the ski area. All of the proceeds from your ticket purchase go to SAC and you get to go skiing. This year the tickets can be bought online thanks to (just click on the link above). Our first ski day is at Mt. Rose on December 17th. We hope to see you there.

The first of a series of warm weather systems impacted the forecast are last night. A total of three systems are expected to allow snowfall to continue into early next week. Ridgetop winds increased last night out of the southwest and are expected to continue through the weekend. Snowfall intensity and ridgetop winds are expected to decrease slightly this afternoon before increasing again during the overnight hours as the second system moves into the forecast area.

Around 2-3" of new snow has fallen overnight throughout the forecast area above 8,000'. Snow level has climbed to just over 7,000' this morning and is expected to remain between 7,000-7,500' during the day today. The new snow is fairly wet and will vary in its ability to bond to the existing old snow surface. The best bonding will occur in areas where the old snow surface is unconsolidated, especially on the more protected northerly aspects. In areas where the new snow is falling on very hard crust surfaces, bonding will occur more slowly. Human triggered sluff and shallow wind slab avalanche activity is possible today in these areas. Avalanche danger will increase during the day today and overnight into Sunday as new snow accumulation continues, especially in wind loaded areas. In areas where new snow is deposited on bare ground, avalanche activity is unlikely today. Snow loading rates and new snow amounts expected with this storm are not expected to cause instability in the weak basal layers of our snowpack. Snowpack failure that occurs is expected at the old/new snow interface. Backcountry travelers venturing into terrain steeper than 30 degrees will need to perform very careful and skilled snowpack observations, as significant variability exists from one slope to another given the current snowpack.

Avalanche danger is LOW with pockets of MODERATE avalanche danger above 8,000', that will become more sensitive to human triggers as the storm progresses. These pockets will be most prevalent on wind loaded NW-N-NE-E aspects above 8,000' on terrain steeper than 35 degrees.

Keep in mind that the overall snowpack is very shallow. You will hit rocks on your skis, snowboard, or snowmobile when you venture off of the snowpacked roads. Getting hurt this time of year makes for a very long winter. Travel at slow speeds to minimize damage to yourself and your equipment. Your best option for recreation remains xc style touring on the higher elevation roads.

Brandon Schwartz, Avalanche Forecaster


Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet): 29 deg. F
Max. temperature at Sierra Crest past 24 hours: 41 deg. F
Average wind direction at Sierra Crest past 24 hours: southwesterly
Average wind speed at Sierra Crest past 24 hours: 50 mph
Maximum wind gust at Sierra Crest past 24 hours: 92 mph
New snow fall at 8,200 feet past 24 hours: 2-3 inches
Total snow depth at 8,200 feet: 13 inches

Mountain Weather Forecast For Today:
Cloudy skies with snow.
Temperature forecast for 8,000 to 9,000 feet: 29 - 35 deg. F
Ridgetop winds forecast for the Sierra Crest: westsouthwesterly at 50 - 70 mph, G 90 mph
Snowfall expected in the next 24 hours: 8 - 15 inches

2 Day Mountain Weather Forecast:
7000 to 8000 Feet
For today, cloudy skies with snow. Daytime highs 36 to 40 degrees F. Snow level 7,000-7,500'. Snow accumulation 2 to 4 inches. Overnight lows 18 to 23 degrees F. Snow level lowering to around 5,000'. Sunday will be cloudy with daytime highs 27 to 33 degrees F. Snow level rising to around 6,000'. Snow accumulation 3 to 5 inches.

Above 8000 Feet
For today, cloudy skies with snow. Daytime highs 29 to 35 degrees F. Snow accumulation 2 to 5 inches. Increasing snowfall intensity overnight. Snow accumulation 6 to 10 inches. Overnight lows 15 to 19 degrees F. Sunday will be cloudy with continued snowfall. Daytime highs 21 to 27 degrees F. Snow accumulation 4 to 8 inches. Moderate to strong westsouthwesterly ridgetop winds for today are expected to continue through Sunday.

The bottom line:

Andy Anderson - 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:

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

For 8000-9000 ft:

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