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 advisory was posted on Monday, February 5th, 2007 at 7:30 pm

The bottom line: Avalanche danger is LOW for all elevations and aspects. Human triggered avalanche activity is unlikely, but not impossible near treeline on sun exposed slopes 35 degrees and steeper.

Thanks to everyone who came out an supported us at Homewood! We will update the financial graph as soon as we get the final numbers, but it looks we still have not made the budget for this year and we are still a long way from the fundraising goal. If you like what we do and want to see it continue, 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. For more details on the current financial situation please click here.

The high pressure ridge that has been sitting over us for a month is forecasted to start breaking down this week. Right now there is a system moving through to the north of us bringing some cloud cover to the area. These clouds will help keep the temperatures warm overnight. Tomorrow we should also continue to see unseasonable warm temps. By Wednesday the high pressure system should be replaced the first of several waves of precipitation that should bring some snowfall to the area. The winds are forecasted to stay light until the arrival of the storm. They should start shifting to the southwest in the next few days.

The air temperatures have been unseasonably warm for the last couple of days. The snowpack is slowly beginning to respond to the warmth. The facetingprocess that has been active throughout the snowpack has slowed down. Below 8000' there are areas where the top 12-18 inches of the snowpack is wet and the rest is starting to form strong bonds and consolidate. When these areas refreeze the snowpack should be quite strong. Just around the corner from these slopes in a more shaded area, only the top 2-3 inches of snow had started to consolidate. Under that thin top layer the weak mix of crusts and facets still dominated the snowpack. Still in other areas observers reported that the only change in the snowpack stratigraphy was a thin (1/8") melt freeze crust forming on the snow surface. Above 8000' on many of the exposed starting zones the snow surface is a mix of supportable wind scour crust, recrystallized faceted snow, and rocks. These open slopes also show a high degree of variability in the snowpack structure and depth. The more sheltered areas above 8000' tend to have a deeper snowpack that is showing less faceting and more stability overall. The variation in the distribution of weak layers and weak snow grains in the snowpack across all elevations yields a great deal of variation in the overall strength of the snowpack. This spatial variability could easily pose problems during the upcoming storm. It would be worthwhile to get out and try to map some of the snow conditions in your favorite terrain. Check out some of the snow pits from around the forecast area here.

Today the springlike temperatures softened the snow surface on all aspects by early afternoon creating fun, consistent riding conditions. With temperatures forecasted to remain above freezing tonight and more warmth for tomorrow expect this trend to continue. Even though the snow is softening up it has not become so wet and unconsolidated that any loose snow or wet slide activity was reported today. While these types of snow instability are not out of the question for tomorrow, any significant activity is unlikely.

No avalanche activity was reported today.

The bottom line: Avalanche danger is LOW for all elevations and aspects. Human triggered avalanche activity is unlikely, but not impossible near treeline on sun exposed slopes 35 degrees and steeper.

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

Andy Anderson, Avalanche Forecaster
Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet):
43 deg. F
Max. temperature at Sierra Crest past 24 hours:
56 deg. F
Average wind direction at Sierra Crest past 24 hours:
easterly to southwest
Average wind speed at Sierra Crest past 24 hours:
10-15 mph
Maximum wind gust at Sierra Crest past 24 hours:
28 mph
New snow fall at 8,200 feet past 24 hours:
0 inches
Total snow depth at 8,200 feet:
34 inches
Mountain Weather Forecast For Tuesday:
Partly cloudy
Temperature forecast for 8,000 to 9,000 feet:
50 deg. F
Ridgetop winds forecast for the Sierra Crest:
South 30 - 40 mph
Snowfall expected in the next 24 hours:
0 inches
2 Day Mountain Weather Forecast:

7000 to 8000 Feet
Tonight, partly cloudy with lows 27 to 35 degrees F and south winds at 20-30 mph. Tuesday, partly cloudy skies with daytime highs around 52 degrees F. Winds are forecasted to be out of the southwest at 20 to 35 mph.

Above 8000 Feet
Tonight, partly cloudy with lows 28 to 34 degrees F and south winds at 30-40 mph. Tuesday, partly cloudy skies with daytime highs around 50 degrees F. Winds are forecasted to be out of the southwest at 30 to 40 mph.

Backcountry Travelers:
We want to hear from you! If you see avalanche activity, or want to share condition information for an area you've been in, please let us know. Call (530) 587-3558 or e-mail us at:

sac_avalanche@fs.fed.us

.

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