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 28, 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. Areas of MODERATE avalanche danger will develop on sun exposed SE-S-SW-W aspects, 37 degrees and steeper in response to daytime warming.

Clear skies and warm days should prevail as a high pressure ridge builds over the forecast area. As this ridge establishes itself the forecast area should see some stronger easterly winds today making air temperatures slightly cooler than yesterday. By tomorrow warmer temperatures should return. The forecast calls for highs in the upper 40's and low 50's during the day and overnight lows around freezing. This weather pattern will continue the melt freeze cycle that started earlier this week.

Observations in the Mt. Lola area yesterday showed that only the top 4 to 6 inches of snow melted during the day on southerly aspects and that a thin (.5 inch) melt freeze crust had formed on northerly aspects due to previous warming. The snow surface under went a solid refreeze last night at all elevations due to overnight lows that were below freezing and radiational cooling of the snowpack. Below the surface the most recent storm snow continues to gain strength through settlement and consolidation on all aspects.

As solar radiation and warming air temperatures melt the snow surface today, free water will dissolve the bonds within the layers of 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. A strong overnight refreeze, slightly cooler temperatures, gradual warming through the week and moderate east winds should all help prevent wet snow instabilities from become 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. Areas of 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): 28 deg. F
Max. temperature at Sierra Crest past 24 hours: 47 deg. F.
Average wind direction at Sierra Crest past 24 hours: East
Average wind speed at Sierra Crest past 24 hours: 20 mph
Maximum wind gust at Sierra Crest past 24 hours: 38 mph
New snow fall at 8,200 feet past 24 hours: 0 inches
Total snow depth at 8,200 feet: 91 inches
Mountain Weather Forecast For Today:
Sunny and warm.
Temperature forecast for 8,000 to 9,000 feet: around 47 deg. F
Ridgetop winds forecast for the Sierra Crest: East at 15 to 20 mph with gusts to 35 mph
Snowfall expected in the next 24 hours: 0 inches
2 Day Mountain Weather Forecast:

7000 to 8000 Feet:
Today, sunny with daytime highs around 51 deg. F. East winds at 10 to 15 mph.

Tonight, clear skies with overnight lows 24 to 32 deg. F and light winds.

For Friday, sunny skies with daytime highs around 54 deg. F. Southwest winds at 10 to 15 mph.

Above 8000 Feet:
Today, sunny with daytime highs around 47 deg. F. East to northeast winds at 15 to 20 mph with gusts to 35 mph.

Tonight, clear skies with overnight lows 31 to 34 deg. F. Southeast winds at 10 mph.

For Friday, sunny skies with daytime highs around 54 deg. F. Southwest winds at 10 to 20 mph with gusts to 30 mph.

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