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 February 29, 2008 7:00 AM
Click here for a detailed map of the SAC forecast area

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Today's Advisory:

This morning the avalanche danger is LOW for all elevations and aspects. MODERATE avalanche danger will develop on sun exposed SE-S-SW-W aspects, 37 degrees and steeper in response to daytime warming.

Overnight the winds shifted back to the southwest and the temperatures climbed into upper 30's and low 40's above 7000'. The forecast calls for the temperatures to climb only a few more degrees through today as a cold front aproaches the area. Some scattered clouds may develop this afternoon and should help keep temperatures slightly lower. This front should cause the winds to increase and temperatures to drop over the next 24 hours. Some scattered snow showers may develop tonight, but the forecast area should see little measurable precipitation from this system.

Observations in the Mt. Rose area yesterday showed that only the top 4 to 6 inches of snow melted during the day on southerly aspects. These southerly aspects softened by mid morning. Some pinwheels and small point release activity occured on the most sun exposed southerly aspects by late afternoon. A mix of breakable melt/freeze crusts, wind crusts, and small pockets of unconsolidated snow exists on the more northerly aspects. Below the surface the snowpack continues to gain strength on all aspects. Even though overnight temperatures remained above freezing the snow surface refroze last night at all elevations due to radiational cooling of the snowpack. This refreeze will not be as robust as previous nights and the snow surface should soften more quickly today.

As solar radiation and warming air temperatures melt the snow surface today, free water will dissolve bonds in the snowpack. This melting process could weaken the snowpack enough for human triggerable wet snow instabilities to form on steep sun exposed SE-S-SW-W aspects. Most of these instabilities should be in the form of human triggerable point release avalanches and surface instabilities like pinwheels; however, wet slab avalanches are not impossible. An overnight refreeze, slightly cooler daytime highs, gradual warming through the week, and some afternoon clouds should all help prevent wet snow instabilities from becoming widespread and should help to keep natural avalanche activity unlikely today.

The bottom line: This morning the avalanche danger is LOW for all elevations and aspects. MODERATE avalanche danger will develop on sun exposed SE-S-SW-W aspects, 37 degrees and steeper in response to daytime warming.

Please send us your snow, weather, and avalanche observations by clicking the submit observations link on our contact page.

Andy Anderson, Avalanche Forecaster

Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet): 39 deg. F
Max. temperature at Sierra Crest past 24 hours: 47 deg. F.
Average wind direction at Sierra Crest past 24 hours: East shifting to the southwest around 11pm last night.
Average wind speed at Sierra Crest past 24 hours: 20 mph
Maximum wind gust at Sierra Crest past 24 hours: 51 mph
New snow fall at 8,200 feet past 24 hours: 0 inches
Total snow depth at 8,200 feet: 89 inches
Mountain Weather Forecast For Today:
Sunny and warm with some clouds devoloping late this afternoon.
Temperature forecast for 8,000 to 9,000 feet: 38 to 45 deg. F
Ridgetop winds forecast for the Sierra Crest: Southwest at 10 to 15 mph with gusts to 25 mph increasing to 20 to 30 mph with gusts to 45 mph in the afternoon
Snowfall expected in the next 24 hours: trace
2 Day Mountain Weather Forecast:

7000 to 8000 Feet:
Today, sunny with daytime highs 43 to 53 deg. F. Southwest winds at 10 to 15 mph with gusts to 30 mph in the afternoon.

Tonight, mostly cloudy with 30% chance of snow showers that produce little measurable accumulation. Overnight lows 25 to 32 deg. F. Winds out of the southwest at 20 to 35 mph with gusts to 50 mph.

For Saturday, partly cloudy skies with a few isolated snow showers in the morning then clearing in the afternoon. Daytime highs 28 to 38 deg. F. Winds out of the southwest at 20 to 30 mph with gusts to 50 mph shifting to the west and decreasing to 10 to 15 mph with gusts to 35 mph in the afternoon.

Above 8000 Feet:
Today, sunny with daytime highs 38 to 45 deg. F. Southwest winds at 20 to 30 mph with gusts to 45 mph.

Tonight, mostly cloudy with 30% chance of snow showers that produce little measurable accumulation. Overnight lows 25 to 35 deg. F. Winds out of the southwest at 30 to 50 mph with gusts to 90 mph.

For Saturday, partly cloudy skies with a few isolated snow showers in the morning then clearing in the afternoon. Daytime highs 25 to 35 deg. F. Winds out of the southwest at 30 to 45 mph with gusts to 80 mph shifting to the west and decreasing to 15 to 30 mph with gusts to 45 mph in the afternoon.

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