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 12, 2006:

December 12, 2006 at 1:00 am

Forecast Discussion:

This advisory was posted on Tuesday, December 12, 2006 at 6:56 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.

Warm, unsettled weather that arrived yesterday afternoon remains over the forecast area this morning. Additional snow and rain will affect the forecast area today, but snow accumulation amounts will remain small. Ridgetop winds increased yesterday afternoon and continued during the overnight hours.

Small isolated pockets of human triggered instability remained visible yesterday in wind loaded areas above 8,000' where recent storm snow sits on top of a hard crust. The storm snow continues to struggle to bond to this layer as additional snowfall load is added in wind loaded areas. All observed avalanche activity has been very small (class 1 on destructive potential scale). Around 2 - 5" of high density new snow fell overnight, with the largest accumulations observed along the Sierra Crest in the northern half of the forecast area. Due to the high density and therefore relatively higher loading created by this new snow, an increase in avalanche activity is expected today. Some very small, isolated natural avalanches are possible today in the northern portion of the forecast area, but the main focus remains human triggering. Due to the high variability of snow at the old snow/recent storm snow interface, instability will remain very pocketed and localized to areas where hard crust surfaces exist at the base of the storm snow.

Near and above treeline, avalanche danger is MODERATE on wind loaded NW-N-NE-E aspects, 35 degrees and steeper. Small, very isolated pockets of CONSIDERABLE danger exist on heavily wind loaded N and NE aspects above 8,000' and 35 degrees and steeper along the Sierra Crest from Hwy 88 extending north to Hwy 49. Below treeline, avalanche danger remains LOW.

Remember that even though you are unlikely to trigger any large avalanches, a small avalanche can be disastrous depending on the terrain. Be aware of secondary exposures such as rockbands, cliffs, gullies, and creek beds, where the consequences of being caught in a small avalanche are greatly magnified.

Brandon Schwartz , Avalanche Forecaster

Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet):
27 deg. F
Max. temperature at Sierra Crest past 24 hours:
28 deg. F
Average wind direction at Sierra Crest past 24 hours:
Average wind speed at Sierra Crest past 24 hours:
40 mph
Maximum wind gust at Sierra Crest past 24 hours:
75 mph
New snow fall at 8,200 feet past 24 hours:
2 - 5 inches
Total snow depth at 8,200 feet:
19 inches
Mountain Weather Forecast For Today:
Cloudy skies with snow showers.
Temperature forecast for 8,000 to 9,000 feet:
28 - 34 deg. F
Ridgetop winds forecast for the Sierra Crest:
westsouthwesterly at 30 - 45 mph, G 65 mph
Snowfall expected in the next 24 hours:
2 - 4 inches
2 Day Mountain Weather Forecast:

7000 to 8000 Feet
For today, cloudy skies with snow showers, heaviest in the morning. Daytime highs of 33 to 38 degrees F. Snow level 7,000' to 7,500'. Snow accumulation 1 to 4 inches. Overnight lows 30 to 35 degrees F. Wednesday will be mostly cloudy with a slight chance of rain and snow showers. Daytime highs 37 to 42 degrees F. Winds out of the west at 15 to 25 mph.

Above 8000 Feet
For today, cloudy skies with snow showers. Daytime highs 28 to 34 degrees F. Snow accumulation 2 to 4 inches. Overnight lows around 28 to 34 degrees F. Scattered snow showers followed by partial clearing. Wednesday will be partly cloudy with a slight chance of snow showers. Daytime highs 32 to 37 degrees F. Moderate westsouthwesterly ridgetop winds for today are expected to shift to moderate westerly on Wednesday.

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:

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