THIS AVALANCHE FORECAST EXPIRED ON December 6, 2019 @ 6:56 am
Avalanche Forecast published on December 5, 2019 @ 6:56 am
Issued by Brandon Schwartz - Tahoe National Forest

Wind last night created the possibility for drifting snow and new wind slabs in some areas today. This has caused an increase to MODERATE avalanche danger for near treeline and above treeline areas. In wind protected areas below treeline, LOW avalanche danger continues.

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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Ridgetop winds out of the SSW picked up to the 30 to 50 mph range for about 9 hours last night along the Sierra Crest in the northern half of the forecast area. Plenty of snow on the ground was available for wind transport last night above 8,000' in near treeline and above treeline areas. New wind slabs are expected to have formed last night above 8,000' on NW-N-NE-E-SE aspects along the Sierra Crest in the northern half of the forecast area. Look for signs of newly formed wind slabs by identifying clues of wind drifted snow such as cornices, wind pillows, snow surface texture, and scouring vs loading patterns causing differing snow depths on either side of ridgelines. Move cautiously around any areas where newly formed wind slabs exist.

Near and above treeline areas that did not receive significant winds last night will soon. As ridgetop winds increase to 40 to 80 mph out of the S tonight and tomorrow, widespread areas of wind drifted snow will increase the size and distribution of wind slabs across the forecast area.

recent observations
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Recent observations from around the forecast area show a right side up snowpack around 2.5 to 5 feet deep in most locations above 7,000'. Continued strength gains have been noted in the bottom and middle portions of the snowpack. Areas below about 8,000' have been affected by recent rain and warming.  Expect to find some surface crusts below 8,000' as the wetted snowpack has begun to refreeze. Above 8,000' the snowpack becomes progressively drier.

Weather and CURRENT CONDITIONS
weather summary

A short lived break in the weather is expected today ahead of the next storm system expected to bring more snow to the region late tomorrow. Ridgetop winds are decreasing this morning following a period of moderate to strong SSW winds last night. Ridgetop winds are forecast to lull during the day today, increasing to strong to gale force out of the S tonight and tomorrow. Air temperatures dropped below freezing last night above 7,000'. Maximum daytime air temperatures are forecast to warm back up above freezing today. High intensity snowfall is expected tomorrow evening into Saturday morning with a second round of high intensity snowfall forecast for Saturday afternoon and evening. Snow levels are expected around 6,500' to 7,000'.

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 23 to 28 deg. F.
Max. temperature: 29 to 34 deg. F.
Average ridgetop wind direction: SSW
Average ridgetop wind speed: 30 mph
Maximum ridgetop wind gust: 54 mph
New snowfall: Trace to 2 inches
Total snow depth: 34 to 55 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Thursday Thursday Night Friday
Weather: Mostly cloudy. Snow levels below 7000 feet increasing to 7000 feet in the afternoon. Chance of precipitation is 0%. Mostly cloudy. Snow levels below 7000 feet. Chance of precipitation is 0%. Mostly cloudy. Snow levels below 7000 feet. Chance of precipitation is 0%.
Temperatures: 35 to 40. deg. F. 25 to 30. deg. F. 36 to 41. deg. F.
Mid Slope Winds: Light winds. Light winds becoming south 10 to 15 mph. South 10 to 15 mph with gusts to 25 mph.
Expected snowfall: No accumulation. | SWE = none. No accumulation. | SWE = none. No accumulation. | SWE = none.
For 8000 ft. to 9000 ft.
Thursday Thursday Night Friday
Weather: Mostly cloudy. Snow levels below 7000 feet increasing to 7000 feet in the afternoon. Chance of precipitation is 0%. Mostly cloudy. Snow levels below 7000 feet. Chance of precipitation is 0%. Mostly cloudy. Snow levels below 7000 feet. Chance of precipitation is 0%.
Temperatures: 32 to 37. deg. F. 24 to 29. deg. F. 33 to 38. deg. F.
Ridge Top Winds: Southwest around 15 mph with gusts to 30 mph. South 15 to 30 mph. Gusts up to 40 mph increasing to 65 mph after midnight. South 30 to 45 mph with gusts to 80 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