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 April 14, 2008 6:50 AM

A map of the SAC forecast area is available on our home page.

1_low.jpg
Today's Advisory:
This morning, avalanche danger is LOW for all elevations and aspects. Isolated pockets of MODERATE danger may develop in sun exposed areas, 38 degrees and steeper in response to daytime warming.

A dry cold front is forecast to pass through the area today, bringing a cool down from this past weekends warm air temperatures. This morning, air temperatures are in the mid 40s at 6,000' to 7,000' and in the mid 30s to low 40s above 8,000'. Southwest ridgetop winds have increased in speed overnight. Ridgetop gusts in excess of 100 mph are expected by this afternoon.

Yesterday, warm air temperatures and a weak snowpack refreeze from the night before allowed the snow surface to become very wet and soft by mid morning. Observations made on Tamarack Peak (Mount Rose area) confirmed that the strongest snow surface refreeze had occurred at the lower elevations due to an air temperature inversion. Ski penetration reached 3 inches on SE aspects at 9,600' by 10:15 am. Ski penetration of up to 8 inches in wet snow was observed on E aspects at 9,600' at 11:00 am. The snow surface is expected to have undergone a weak refreeze from radiational cooling last night at all elevations, despite above freezing air temperatures.

Today, solar radiation and above freezing air temperatures will quickly melt the thin surface melt-freeze crust that formed overnight. Maximum daytime air temperatures for today are forecast at 10 to 15 deg. F. below yesterday's highs. Strong winds will further help to decrease the rate of snow surface melting, especially when compared to what occurred this past weekend. With a significant decrease in free water production in the upper snowpack, a minimal amount of wet loose surface snow instability is expected for today. Deep wet slab avalanches remain unlikely at this time.

The bottom line: This morning, avalanche danger is LOW for all elevations and aspects. Isolated pockets of MODERATE danger may develop in sun exposed areas, 38 degrees and steeper in response to daytime warming.

Brandon Schwartz, Avalanche Forecaster

Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet): 35 deg. F
Max. temperature at Sierra Crest past 24 hours: 55 to 58 deg. F.
Average wind direction at Sierra Crest past 24 hours: Southwest
Average wind speed at Sierra Crest past 24 hours: 33 mph
Maximum wind gust at Sierra Crest past 24 hours: 61 mph
New snowfall at 8,200 feet past 24 hours: 0 inches

Total snow depth at 8,200 feet: 68 inches
Mountain Weather Forecast For Today:
Partly cloudy, cooler, and very windy.
Temperature forecast for 8,000 to 9,000 feet: 38 to 46 deg. F
Ridgetop winds forecast for the Sierra Crest: Southwest at 35 to 55 mph with gusts to 90 mph, increasing to 105 mph in the afternoon.
Snowfall expected in the next 24 hours: 0 to trace inches

2 Day Mountain Weather Forecast:

7000 to 8000 Feet:

Today, partly cloudy skies with daytime highs 46 to 54 deg. F. Southwest winds at 15 to 25 mph with gusts to 45 mph. Winds increasing to 30 to 45 mph with gusts to 60 mph by the afternoon.

Tonight, mostly cloudy skies with isolated snow showers. Overnight lows 19 to 24 deg. F. Southwest winds at 20 to 30 mph with gusts to 50 mph. Winds decreasing to west at 15 to 20 mph after midnight.

For Tuesday, mostly cloudy skies in the morning. Skies becoming partly cloudy as the day progresses. Daytime highs 31 to 37 deg. F. West winds at 10 to 15 mph.

Above 8000 Feet:

Today, partly cloudy skies with daytime highs 38 to 46 deg. F. Southwest winds at 35 to 55 mph with gusts to 90 mph. Gusts increasing to 105 mph in the afternoon.

Tonight, mostly cloudy skies with isolated snow showers. Overnight lows 15 to 21 deg. F. Southwest winds at 35 to 50 mph with gusts to 90 mph. Winds decreasing to 25 to 35 mph with gusts to 65 mph after midnight.

For Tuesday, mostly cloudy skies in the morning. Skies becoming partly cloudy as the day progresses. Daytime highs 28 to 33 deg. F. Northwest winds at 15 to 25 mph with gusts to 45 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:
	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.