THIS AVALANCHE ADVISORY EXPIRED ON March 13, 2015 @ 6:45 am
Avalanche Advisory published on March 12, 2015 @ 6:45 am
Issued by Andy Anderson - Tahoe National Forest

Avalanche danger should remain LOW for all elevations and aspects today. Some shallow, small, isolated wind deposits or loose wet snow instabilities that do not entrain enough snow to do much more than knock a person off balance might exist on some isolated terrain features steeper than 35 degrees. Continue to use normal caution when traveling in the backcountry.

1. Low

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Above Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1. Low

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Near Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1. Low

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Below Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
    Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Avalanche Problem 1: Normal Caution
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  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
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    Very Large
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    Small

Yesterday's snow and rain did little to change the state of the snowpack. The new snow accumulation did not provide enough material to form significant slabs on top of the old snow surfaces. East winds today may scour snow away from any of the small wind deposits that formed yesterday, but they should not form significant wind slabs on the leeward aspects due to the minimal snow amounts available for transport. A few small, shallow wind deposited drifts may form or linger near ridge lines.

The rain did melt some snow and create wet snow in many areas below 8000 ft, but it should have started to refreeze last night after the storm ended. This refreeze should melt today due to warmer temperatures and March sunshine and wet surface snow will return to the E-SE-S-SW-W aspects. Some minor loose wet snow instabilities like roller balls, pinwheels, and small isolated loose wet snow sluffs may occur on steep sun-exposed aspects today.  Any of the instabilities that might form today would remain small and isolated and should not involve enough snow to bury a person, but they could push someone off course or knock a person over.

recent observations

Yesterday on Tamarack Peak, a crust existed on all aspects underneath 1 inch of new snow. On the northerly aspects this crust was thin and breakable and likely formed due to high elevation rain at the start of yesterday's small storm. Snowpit tests indicated a stable and strong snowpack that continues to consolidate and form bonds between its layers. In areas that typically experience heavy wind loading, wind deposited snow up to 2 inches in depth existed. Snow level in this area seemed to fluctuate between 8000 and 8500 ft. during the day.

Weather and CURRENT CONDITIONS
weather summary

Yesterday the small system that brought snow and rain to the area deposited 1 to 2 inches of snow above 8000 ft. in most areas and up to 3 inches in some spots along the Sierra Crest. Below 8000 ft. most of the precipitation fell as rain since snow levels climbed higher than expected. This system moved out of the area last night, and another high pressure ridge moved in to take its place. Expect partly cloudy to mostly sunny skies today and moderate east winds as this ridge settles over the region. The winds should begin to decrease this afternoon and evening. By tomorrow the forecast calls for light winds at all elevations. Temperatures should begin a warming trend with daytime highs above 7000 ft. in the low to mid 40's today and upper 40's to low 50's by tomorrow.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 28 to 32 deg. F.
Max. temperature in the last 24 hours: 34 to 39 deg. F.
Average wind direction during the last 24 hours: Soutwest shifting to northeast after midnight
Average wind speed during the last 24 hours: Yesterday: 35 mph | Last night: 15 mph
Maximum wind gust in the last 24 hours: 60 mph
New snowfall in the last 24 hours: 1 to 3 inches
Total snow depth: 26 to 45 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Thursday Thursday Night Friday
Weather: Partly cloudy becoming sunny Clear Partly cloudy
Temperatures: 41 to 46 deg. F. 28 to 34 deg. F. 47 to 54 deg. F.
Wind Direction: East East Variable
Wind Speed: 5 to 10 mph in the morning increasing to 10 to 15 mph with gusts to 25 mph in the afternoon 10 to 15 mph in the evening decreasing overnight Light
Expected snowfall: 0 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Thursday Thursday Night Friday
Weather: Partly cloudy becoming sunny Clear Partly cloudy
Temperatures: 38 to 44 deg. F. 29 to 35 deg. F. 46 to 52 deg. F.
Wind Direction: East East Southeast
Wind Speed: 15 to 25 mph with gusts to 30 mph increasing to 40 mph in the afternoon 15 to 25 mph with gusts to 35 mph 10 to 15 mph in the morning decreasing in the afternoon
Expected snowfall: 0 in. 0 in. 0 in.
Disclaimer

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.