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 2, 2008 6:47 AM
Click here for a detailed map of the SAC forecast area

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Today's Advisory:

Avalanche danger is LOW for all elevations and aspects. Normal caution is advised. Avalanche danger will increase in response to significant new snowfall during the evening and overnight hours.

Increasing cloud cover and increasing ridgetop winds are expected today as a significant Pacific storm system approaches the forecast area. Ridgetop winds have been light to moderate from the west southwest for the past 24 hours. Some warmer air will move into the forecast area today ahead of the approaching storm, but air temperatures above 6,500' are expected to remain below freezing. Snow showers and light snowfall accumulation are possible during the day today, but significant snowfall rates are not expected to begin until this evening.

Yesterday, light to moderate ridgetop winds were unable to scour snow from high density slabs that exist near and above treeline. No wind transport or new slab formation was observed. Snowpit data taken from NE-E aspects above and below treeline on Hidden Peak (West Shore Tahoe area) and from N-NE-E aspects near treeline on Tamarack Peak (Mount Rose area), all indicate a stable snowpack. Layer bonding tests yielded moderate to hard force shears in all cases. Informal observations such as hand pits and body weight loading of test slopes indicated that areas of instability that existed in the morning became more stable as the day progressed.

Today, avalanche activity is unlikely due to the increased layer bond strength that has occurred within the snowpack over the past 24 hours. Ridetop winds will increase today, but minimal snow is available for wind transport. No new wind loading or slab formation is expected prior to the onset of high snowfall rates that are forecast for this evening. Avalanche danger is not expected to rise until the evening and overnight hours when the approaching storm brings significant new snowfall to the forecast area.

The bottom line: Avalanche danger is LOW for all elevations and aspects. Normal caution is advised. Avalanche danger will increase in response to significant new snowfall during the evening and overnight hours.

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

Brandon Schwartz, Avalanche Forecaster

Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet): 8 deg. F
Max. temperature at Sierra Crest past 24 hours: 18 deg. F
Average wind direction at Sierra Crest past 24 hours: West southwest
Average wind speed at Sierra Crest past 24 hours: 30 mph
Maximum wind gust at Sierra Crest past 24 hours: 51 mph
New snow fall at 8,200 feet past 24 hours: 0 to trace inches
Total snow depth at 8,200 feet: 85 to 95 inches

Mountain Weather Forecast For Today:
Cloudy skies with a chance of snow.
Temperature forecast for 8,000 to 9,000 feet: 21 to 27 deg. F
Ridgetop winds forecast for the Sierra Crest: Southwest at 20 to 35 mph with gusts to 50 mph, gusts increasing to 65 mph in the afternoon.
Snowfall expected in the next 24 hours: 12 to 20 inches

2 Day Mountain Weather Forecast:

7000 to 8000 Feet:
Today, mostly cloudy with a chance of snow in the morning. Snow likely in the afternoon. Snow accumulation up to 3 inches. Daytime highs 25 to 30 deg. F. Southwest winds at 10 mph, increasing to 15 to 25 mph with gusts to 35 mph in the afternoon.

Tonight, cloudy with snow. Snow accumulation 12 to 18 inches. Overnight lows 17 to 21 deg. F. Southwest winds at 20 to 30 mph with gusts to 45 mph.

For Sunday, snow in the morning. Mostly cloudy with a chance of snow showers in the afternoon. Snow accumulation 5 to 10 inches. Daytime highs 20 to 27 deg. F. Southwest winds at 25 to 35 mph, shifting to west at 15 to 25 mph in the afternoon.

Above 8000 Feet:
Today, cloudy with a chance of snow in the morning. Snow likely in the afternoon. Snow accumulation up to 3 inches. Daytime highs 21 to 27 deg. F. Southwest winds at 20 to 35 mph with gusts to 50 mph, increasing to gusts to 65 mph in the afternoon.

Tonight, cloudy with snow. Snow accumulation 12 to 18 inches. Overnight lows 13 to 19 deg. F. Southwest winds at 40 to 50 mph, decreasing to 30 to 50 mph after midnight. Wind gusts to 100 mph.

For Sunday, snow in the morning. Mostly cloudy with a chance of snow showers in the afternoon. Snow accumulation 5 to 10 inches. Daytime highs 16 to 22 deg. F. Southwest winds at 35 to 45 mph with gusts to 60 mph. Winds shifting to west at 20 to 30 mph with gusts to 40 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:
	Saturday:	Saturday Night:	Sunday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.
For 8000-9000 ft:
	Saturday:	Saturday Night:	Sunday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.