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 January 21, 2007:

January 21, 2007 at 1:00 am

Forecast Discussion:

This advisory was posted on Sunday, January 21, 2007 at 5:45 pm

The bottom line: Avalanche danger is LOW for all elevations and aspects.

First of all we want to say a heartfelt "thank you" to everyone who has made a contribution to the Avalanche Center this week. The show of support in both cash donations and Kirkwood Ski Day ticket purchases has been amazing! We still have a long way to go to reach our '06-'07 budget and even farther to meet our fund raising goal, but thanks to your generosity we are much closer. For more details on the current financial situation please click here. Our next fund raiser is another ski day on February 4th at Homewood. Tickets are on sale now at If you can't make it but would still like to help out, please make a tax deductible donation directly to us via Paypal or by sending a check to our address listed above, c/o the Truckee Ranger Station. Your support is what makes the Sierra Avalanche Center possible.

A dry but windy weather disturbance passed by the forecast area today. This brought higher than forecast northeast to east winds over the Sierra Crest. Lower than forecast maximum air temperatures were observed today for areas above 7,000'. Ridgetop winds are beginning to decrease this evening and are expected to further decrease overnight and into Monday. Air temperature inversion is expected to form after the passage of today's weather system, bringing some warming to the upper elevations over the next several days.

Faceting of snow crystals continues to dominate the minor day to day change of the snowpack. Moderate to hard force shears continue to emerge on faceted layers in response to layer bonding tests, especially in the upper half of the snowpack immediately above and below crust layers. These shears have been observed both along the Sierra Crest and in the Mount Rose area. Despite a continued gradual weakening of the snowpack over the past two weeks, widespread snowpack stability exists. Current shears are a possible concern for future snowpack instability. Continued observations will determine their significance over the next few weeks. Strong northeast to east winds last night and today redistributed snow from the few remaining areas where snow was available for wind transport. No new hazardous wind slab formation is expected in lee areas from the today's wind event, due to the minor amounts of wind transported snow. Natural and human triggered avalanche events remain unlikely.

Gradual warming of air temperatures this week will allow for melt-freeze conditions on southerly aspects up to 8,000' and possibly higher. This will depend on the strength of the expected air temperature inversion and exactly how much warming occurs at the upper elevations. Sun softened southerly aspects will likely provide the best sliding conditions over the next few days.

The bottom line: Avalanche danger is LOW for all elevations and aspects.

The next scheduled update to this advisory will occur tomorrow afternoon.

Brandon Schwartz, Avalanche Forecaster


Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet): 10 deg. F
Max. temperature at Sierra Crest past 24 hours: 18 deg. F
Average wind direction at Sierra Crest past 24 hours: northeasterly to easterly
Average wind speed at Sierra Crest past 24 hours: 53 mph
Maximum wind gust at Sierra Crest past 24 hours: 112 mph
New snow fall at 8,200 feet past 24 hours: 0 inches
Total snow depth at 8,200 feet: 38 inches (corrected for recent sensor error)

Mountain Weather Forecast For Monday:
Sunny skies
Temperature forecast for 8,000 to 9,000 feet: 32 - 37 deg. F
Ridgetop winds forecast for the Sierra Crest: easterly 20 - 30 mph with gusts to 45 mph.
Snowfall expected in the next 24 hours: 0 inches

2 Day Mountain Weather Forecast:
7000 to 8000 Feet
Tonight, clear skies with lows 10 to 20 degrees, F. Northeast winds 15 to 20 mph, gusting to 35 mph. Monday, sunny skies with daytime highs around 38 degrees F. East winds 5 to 10 mph, gusting to 20 mph are expected.

Above 8000 Feet
Tonight, clear skies with lows 13 to 23 degrees F. Northeast winds 35 to 55 mph, gusting to 80 mph decreasing to 60 mph after midnight. Monday, sunny skies with daytime highs around 33 degrees F. East winds 20 to 30 mph, gusting to 45 mph are expected.

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:

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