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 Wednesday, April 18th, 2007 at 7:10 am

The bottom line: Near and above treeline the avalanche danger is LOW. Very small, isolated pockets of MODERATE avalanche danger exist on recently wind loaded N-NE-E aspects 35 degrees and steeper. Any avalanche activity on these slopes today should be very small, isolated soft slabs and loose snow sluffs. Below treeline, avalanche danger is LOW.

The front that pushed into the area last night has brought cold winter air back to the forecast area. After some more scattered snow showers this morning, skies should clear today. As this front passes to the east today the winds should calm down before they start to increase ahead of the next low pressure system. By tomorrow a larger low pressure system should move into the area bringing another increase in the southwest winds and more snow. Air temperatures are forecasted to remain cold for through Friday.

Last night 3-5 inches of new, cold snow fell across the forecast area. This snow fell on a surface that is a mix of hard wind, scoured crusts, consolidating storm snow from earlier this week, and bare ground. The moderate to strong southwest winds transported this new snow onto the N-NE-E aspects and new wind slabs have started to form on these aspects. These wind slabs are mostly sitting on the wind scoured, old, frozen melt-freeze surface that was exposed by the east winds after the last burst of snow. Bonding between these newly forming windslabs and this old melt-freeze crust should be suspect. However, lack of significant accumulation and decreasing wind speeds today should cause these newly formed windslabs to remain small and isolated.

Natural avalanche activity is unlikely today. Snowpack instability is expected to be limited to human triggering of very small, isolated soft slabs and loose snow sluffs. It should only involve the new snow from last night sliding off the old melt freeze crusts. The recently windloaded N-NE-E aspects near and above treeline will be the areas that hold more of these isolated pockets than anywhere else.

Riding conditions today will be variable and fast. Expect to see dust on crust conditions on the newly wind loaded N-NE-E aspects, dust on a sometimes breakable crust on the the wind sheltered NW-W and SE aspects, bare ground that is barley covered on other aspects, and wind scoured crusts on the windward exposed aspects. Accumulations from the last few storms have provided enough snow to barely hide some of the rocks and trees that have emerged in the recent weeks. Be careful out there and watch out for these obstacles.

The bottom line: Near and above treeline the avalanche danger is LOW. Very small, isolated pockets of MODERATE avalanche danger exist on recently wind loaded N-NE-E aspects 35 degrees and steeper. Any avalanche activity on these slopes today should be very small, isolated soft slabs and loose snow sluffs. Below treeline, avalanche danger is LOW.

Thanks to all of our sponsors, the ski days, and everyone who has donated funding this winter, we have met our operating budget for this season and have a start on next year's funding. For more details about our financial situation please click here.

Andy Anderson , Avalanche Forecaster
Today's Central Sierra Weather Observations:
0600 temperature at Sierra Crest (8,700 feet):
11 deg. F
Max. temperature at Sierra Crest past 24 hours:
36 deg. F
Average wind direction at Sierra Crest past 24 hours:
Southwest
Average wind speed at Sierra Crest past 24 hours:
40 mph
Maximum wind gust at Sierra Crest past 24 hours:
84 mph
New snow fall at 8,200 feet past 24 hours:
3 inches
Total snow depth at 8,200 feet:
57 inches
Mountain Weather Forecast For Today:
Partly cloudy with scattered snow showers in the morning
Temperature forecast for 8,000 to 9,000 feet:
17 - 23 degrees F.
Ridgetop winds forecast for the Sierra Crest:
Northwest 20 - 30 mph, gusting to 45 mph. Decreasing in the afternoon
Snowfall expected in the next 24 hours:
less than 1 inch
2 Day Mountain Weather Forecast:

7000 to 8000 Feet:
Today, partly cloudy with scattered snow showers in the morning and daytime highs 26 to 32 degrees F. Northwest winds 15 to 25 mph. Tonight, partly cloudy skies with overnight lows 16 to 22 degrees F. Northwest winds at 5 to 15 mph. Thursday, mostly cloudy with a chance of snow showers in the afternoon. Daytime highs 34 to 40 degrees F. Southwest winds 15 to 25 mph.

Above 8000 Feet:
Today, partly cloudy with scattered snow showers in the morning and daytime highs 17 to 23 degrees F. Northwest winds 20 to 30 mph with gusts up to 45 mph in the morning. Winds diminishing to 15 to 25 mph in the afternoon. Tonight, partly cloudy skies with overnight lows 15 to 20 degrees F. Northwest winds 10 to 15 mph becoming south by daybreak. Thursday, mostly cloudy with a chance of snow showers in the afternoon. Daytime highs 24 to 31 degrees F. Southwest winds 20 to 30 mph. Gusts up to 60 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:
	Wednesday:	Wednesday Night:	Thursday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.
For 8000-9000 ft:
	Wednesday:	Wednesday Night:	Thursday:
Weather:
Temperatures:	deg. F.	deg. F.	deg. F.
Wind direction:
Wind speed:
Expected snowfall:	O in.	O in.	O in.