THIS AVALANCHE ADVISORY EXPIRED ON March 24, 2017 @ 6:58 am
Avalanche Advisory published on March 23, 2017 @ 6:58 am
Issued by Andy Anderson - Tahoe National Forest

MODERATE avalanche danger will exist on all aspects today due to rapid warming weakening the recent snow. Widespread loose wet avalanches will be likely today. The warming will also weaken existing slabs making human triggered wind and wet slab avalanches possible today as well.  Evaluate the snowpack and terrain carefully to identify where avalanche problems may exist and plan a route that avoids the potential avalanche problems. 

2. Moderate

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Above Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

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Near Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

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Below Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
    Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Loose Wet
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Widespread loose wet avalanche activity will become likely at all elevations today as the intense March sunshine warms up the new snow for the first time. Loose wet avalanches could entrain enough snow to cause problems for backcountry travelers and some larger loose wet avalanches that involve enough snow to bury a person could occur. The largest and most widespread loose wet avalanche activity should occur on sun-exposed E-SE-S-SW-W aspects but some loose wet activity could also occur on northerly aspects that receive sunshine.

Avalanche Problem 2: Wind Slab
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The sunshine will also weaken the wind slabs that formed during the storm by warming them up and melting the bonds holding the snowpack together. Avalanches involving these sun-weakend and now wet wind slabs will be possible today. Sun-exposed E-SE and W aspects hold the best potential for these slab avalanches but wind slab avalanches will also be possible on NW-N-NE aspects especially in areas where these northerly aspects see some sun. Some wet slab avalanches may also be possible on sun-exposed SW and S aspects due to sun on new snow. 

recent observations

Yesterday observations from below 7500 ft. on Hidden Peak found about 2 inches of new snow on top of a supportable frozen rain crust with wet snow below the crust. Above 7500 ft. new snow totals increased and up to 6 inches of new snow existed at the higher elevations. Winds remained light in this area yesterday and no signs of problematic wind slabs existed in the expected locations. Ski cuts on steep test slopes did trigger some small loose dry sluffs. Across the Lake on Tamarack Peak 6 to 12 inches of new snow existed. Some minor cracking occurred near the top of the Proletariate, but the cracks remained small and did not propagate very far.  

Weather and CURRENT CONDITIONS
weather summary

The forecast calls for sunny skies and light winds today as a small and short-lived high-pressure ridge moves over the region. Daytime highs should climb into the upper 30's and low 40's above 7000 ft. By tonight cloud cover and southwest winds should start to increase again as another spring storm approaches the area. This storm should arrive Friday bringing more snow and wind with it. Snow levels should remain between 6000 and 7000 ft. The forecast calls for up a foot of additional snow by Friday evening. 

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 17 to 23 deg. F.
Max. temperature in the last 24 hours: 26 to 33 deg. F.
Average wind direction during the last 24 hours: SW to NE and NW
Average wind speed during the last 24 hours: 10 to 20 mph
Maximum wind gust in the last 24 hours: 47 mph
New snowfall in the last 24 hours: 2 to 6 inches
Total snow depth: 125 to 176 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Thursday Thursday Night Friday
Weather: Sunny Mostly cloudy with a slight chance of showers after midnight Cloudy with a chance of rain and snow in the morning. Rain and snow becoming widespread in the afternoon.
Temperatures: 38 to 44 deg. F. 28 to 33 deg. F. 31 to 37 deg. F.
Wind Direction: Variable Southwest South shifting to southwest
Wind Speed: Light 10 to 15 mph with gusts to 30 mph increasing to 40 mph after midnight 15 to 20 mph increasing to 20 to 30 mph with gusts to 45 mph in the afternoon
Expected snowfall: 0 in. 0 in. 2 to 6 in.
For 8000 ft. to 9000 ft.
Thursday Thursday Night Friday
Weather: Sunny Mostly cloudy with a slight chance of snow showers after midnight Cloudy with a chance of snow in the morning. Snow becoming widespread in the afternoon.
Temperatures: 35 to 40 deg. F. 26 to 31 deg. F. 30 to 36 deg. F.
Wind Direction: West Southwest Southwest
Wind Speed: 10 to 15 mph with gusts to 35 mph 20 to 30 mph with gusts to 50 mph increasing to 70 mph after midnight 35 to 55 mph with gusts to 80 mph increasing to 100 mph in the afternoon
Expected snowfall: 0 in. 0 in. 3 to 8 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.

For a recorded version of the Avalanche Advisory call (530) 587-3558 x258