THIS AVALANCHE FORECAST EXPIRED ON December 20, 2018 @ 6:54 am
Avalanche Forecast published on December 19, 2018 @ 6:54 am
Issued by Steve Reynaud - Tahoe National Forest

Moderate Avalanche Danger will exist today due to a wind slab avalanche problem.  Wind slab avalanches will remain possible in near and above treeline terrain.  Low Avalanche Danger will exist in below treeline terrain.

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.

1. Low

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Below Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
    Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Wind Slab
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Wind slab avalanches will remain possible today in near and above treeline terrain, mostly on N-NE-E aspects with some potential on cross loaded NW and SE aspects.  Wind slabs that formed yesterday could still be reactive today.  Many wind slab avalanches occurred yesterday, both human and natural triggered, and up to D2 in size.  While winds are forecasted to switch to the S today and remain moderate to strong, active wind transport should taper off due to a decrease in available snow for transport.

Look for signs of previous wind loading and cornice formation.  Cornice failure caused some of the wind slab avalanches seen yesterday.  The best snow conditions will be in protected below treeline terrain away from the wind effected snow. 

recent observations
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*  Up to 10 different wind slab avalanches were observed yesterday in the Mt. Judah area.  All were on NE-E aspects, small in size - D1, and most did not extend very far downslope.  Natural cornice failure looked to be responsible for the majority of these avalanches.

*  A D2 skier triggered wind slab avalanche was reported from Jackson Meadows (Independence Lakes area).  Avalanche occurred on a north aspect in above treeline terrain, with crown reported up to 3' deep.  Limited details are available.

*  Strong SW winds throughout the day yesterday observed in most near and above treeline areas throughout the forecast region.  Snow transport was reported as strong to intense at times, with wind slab development reported from many areas.

Weather and CURRENT CONDITIONS
weather summary

High pressure will strengthen over our area today bringing decreased winds and warming temperatures.  Today is expected to be sunny with temperatures into the mid to high 40's above 7000'.  Our next storm is forecasted for late Thursday into Friday, with increasing winds and light precipitation.  Early next week brings the chances of a larger storm.

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 26 to 39 deg. F.
Max. temperature: 39 deg. F.
Average ridgetop wind direction: SW to NW
Average ridgetop wind speed: 15 to 50 mph
Maximum ridgetop wind gust: 58 mph
New snowfall: 0 inches
Total snow depth: 26 to 31 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Wednesday Wednesday Night Thursday
Weather: Sunny. Snow levels 7000 feet increasing to 8000 feet in the afternoon. Chance of precipitation is 0%. Clear. Snow levels 8000 feet decreasing to below 7000 feet after midnight. Chance of precipitation is 0%. Sunny then becoming partly cloudy. Snow levels 7000 feet. Chance of precipitation is 0%.
Temperatures: 44 to 49. deg. F. 27 to 33. deg. F. 45 to 50. deg. F.
Mid Slope Winds: Light winds. Light winds becoming southwest 10 to 15 mph with gusts to 30 mph after midnight. Southwest 15 to 25 mph. Gusts up to 40 mph increasing to 50 mph in the afternoon.
Expected snowfall: No accumulation. | SWE = none. No accumulation. | SWE = none. No accumulation. | SWE = none.
For 8000 ft. to 9000 ft.
Wednesday Wednesday Night Thursday
Weather: Sunny. Snow levels 7000 feet increasing to 8000 feet in the afternoon. Chance of precipitation is 0%. Clear. Snow levels 8000 feet decreasing to below 7000 feet after midnight. Chance of precipitation is 0%. Sunny then becoming partly cloudy. Snow levels below 7000 feet increasing to 7500 feet in the afternoon. Chance of precipitation is 0%.
Temperatures: 43 to 49. deg. F. 31 to 36. deg. F. 42 to 47. deg. F.
Ridge Top Winds: South 15 to 25 mph. Gusts up to 50 mph decreasing to 30 mph in the afternoon. South 15 to 30 mph. Gusts up to 45 mph increasing to 70 mph after midnight. Southwest 25 to 40 mph with gusts to 75 mph.
Expected snowfall: No accumulation. | SWE = none. No accumulation. | SWE = none. No accumulation. | SWE = none.
Disclaimer

This avalanche forecast is provided through a partnership between the Tahoe National Forest and the Sierra Avalanche Center. This forecast 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 forecast applies only to backcountry areas outside established ski area boundaries. This forecast describes general avalanche conditions and local variations always occur. This forecast expires 24 hours after the posted time unless otherwise noted. The information in this forecast is provided by the USDA Forest Service who is solely responsible for its content.

For a recorded version of the avalanche forecast call (530) 587-3558 x258