THIS AVALANCHE FORECAST EXPIRED ON December 15, 2019 @ 6:50 am
Avalanche Forecast published on December 14, 2019 @ 6:50 am
Issued by Brandon Schwartz - Tahoe National Forest

CONSIDERABLE avalanche danger exists above treeline and near treeline where wind drifted snow has formed into wind slabs. MODERATE avalanche danger exists below treeline due to the possibility of storm slabs and loose dry avalanches.

3. Considerable

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Above Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

3. Considerable

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Near Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

2. Moderate

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Below Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
    Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Wind Slab
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Recently wind drifted snow forming into wind slabs in lee areas is the main avalanche concern for today. Expect to encounter newly formed wind slabs in near treeline and above treeline terrain on NW-N-NE-E-SE aspects. Avalanche size up to D2 is expected. Freshly enhanced cornices are weak and could collapse easily under the weight of a person today.

Make a plan to avoid wind slabs today. There are lots of other slopes to utilize. Identify the most likely location of wind slabs by using clues of recently wind drifted snow including cornices, wind pillows, and scouring vs deposition patterns along ridgelines.

Avalanche Problem 2: Storm Slab
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Low end snowfall accumulations and a warm to cold storm have made conditions borderline for new storm slabs to have formed over the last 24 hours. If storm slab instability does not exist, expect loose dry avalanche problems (sluff) instead. If storm slabs did form, they could be encountered in wind protected areas below treeline on any aspect. The expected avalanche size is D1.

Areas of snow surface cracking or recent avalanches in wind protected areas below treeline are signs of storm slab instability. Using lower angle slopes and avoiding steeper slopes above is a way to manage either a storm slab or loose dry avalanche problem.

recent observations
Submit Observations

Observations made yesterday in the Mount Rose and Carson Pass areas revealed blowing snow and fragile new cornices. Wind slabs were forming in lee areas where wind drifted snow was depositing. Snowpack stability was on a decreasing trend during the afternoon and evening hours.

Recent observations from around the forecast area indicate strong layer bonding in the lower and middle portions of the snowpack. Current avalanche problems are focused on the upper portion of the snowpack.

Weather and CURRENT CONDITIONS
weather summary

The storm system from the past 24 hours is tapering down. Snow levels have fallen below 6,000'. Ridgetop winds remain out of the SW and are decreasing in speed. A break in the weather is expected today with partial clearing of cloud cover this afternoon. A weak weather system is forecast to move through tonight providing some additional snow showers. Sunny skies and a continued air temperature cooling trend are expected for tomorrow.

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 20 to 26 deg. F.
Max. temperature: 29 to 36 deg. F.
Average ridgetop wind direction: SW
Average ridgetop wind speed: 45 mph
Maximum ridgetop wind gust: 121 mph
New snowfall: 4 to 10 inches
Total snow depth: 45 to 54 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Saturday Saturday Night Sunday
Weather: Mostly cloudy then becoming partly cloudy. Chance of snow. Snow levels below 7000 feet. Chance of precipitation is 50%. Mostly cloudy. Snow likely. Snow levels below 7000 feet. Chance of precipitation is 70%. Partly cloudy then becoming sunny. Snow levels below 7000 feet. Chance of precipitation is 5%.
Temperatures: 29 to 34. deg. F. 15 to 21. deg. F. 24 to 29. deg. F.
Mid Slope Winds: Southwest 15 to 25 mph. Gusts up to 35 mph. West around 15 mph with gusts to 30 mph. West around 10 mph becoming north in the afternoon.
Expected snowfall: 80% probability up to 1 inch. 20% probability of 1 to 3 inches. | SWE = less than 0.10 inch. 60% probability of 1 to 3 inches. 40% probability of 3 to 5 inches. | SWE = up to 0.20 inch. No accumulation. | SWE = none.
For 8000 ft. to 9000 ft.
Saturday Saturday Night Sunday
Weather: Mostly cloudy then becoming partly cloudy. Chance of snow. Snow levels below 7000 feet. Chance of precipitation is 50%. Mostly cloudy. Snow likely. Snow levels below 7000 feet. Chance of precipitation is 75%. Partly cloudy. Snow levels below 7000 feet. Chance of precipitation is 5%.
Temperatures: 24 to 30. deg. F. 11 to 16. deg. F. 19 to 25. deg. F.
Ridge Top Winds: Southwest 30 to 50 mph decreasing to 15 to 30 mph in the afternoon. Gusts up to 60 mph in the morning. Southwest to west 15 to 25 mph with gusts to 40 mph. Northwest 15 to 25 mph with gusts to 40 mph.
Expected snowfall: 80% probability of up to 1 inch. 20% probability of 1 to 3 inches. | SWE = up to 0.15 inch. 60% probability of 1 to 3 inches. 40% probability of 3 to 5 inches. | SWE = up to 0.20 inch. 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