THIS AVALANCHE FORECAST EXPIRED ON December 27, 2019 @ 6:54 am
Avalanche Forecast published on December 26, 2019 @ 6:54 am
Issued by Brandon Schwartz - Tahoe National Forest

MODERATE avalanche danger exists above treeline and near treeline due to an overnight wind shift to the ENE that has likely drifted snow and formed new wind slabs. LOW avalanche danger continues for wind protected areas below treeline.

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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Conditions changed overnight with a wind shift to ENE. Snow on the ground has likely been scoured and drifted into new wind slabs in near treeline and above treeline terrain. The vast majority of wind slabs are now expected on SE-S-SW-W-NW-N aspects. Avalanche size up to D2 is possible.

Wind slabs will not necessarily exist in the usual palaces today. Look closely for signs of where the most recent drifting has occurred. It is different from what occurred over the past two days under SW wind conditions. Identify clues such as blowing snow, wind scouring along ridges, snow surface patterns indicative of scouring vs deposition, new wind pillows, and shooting cracks as indicators of wind slab development. Use these clues to identify where problematic wind slabs may exist and communicate within your group on how best to manage the combination of terrain and this avalanche problem.

recent observations
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* At sunrise on Dec 24, 4 to 12 inches of snow existed along ridgetop areas available for transport by SW winds.

* Winds increased from the SW by late morning on Dec 24 and blowing/drifting snow was reported.

* SW winds decreased on Dec 25, shifted to the ENE in the evening and became strong overnight.

Weather and CURRENT CONDITIONS
weather summary

A weather system is passing by off the coast and will move inland through SoCal today. Ridgetop winds out of the ENE increased around 5 pm yesterday, gusting to 71 mph last night. Wind speeds have decreased a bit this morning. ENE winds are expected to continue at moderate speed into tomorrow. Cloud cover will continue today, clearing overnight into tomorrow. Near to below average air temperatures are forecast for the next several days.

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 12 to 17 deg. F.
Max. temperature: 14 to 24 deg. F.
Average ridgetop wind direction: ENE
Average ridgetop wind speed: 32 mph
Maximum ridgetop wind gust: 71 mph
New snowfall: Trace to 1 inches
Total snow depth: 46 to 53 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. Slight chance of snow in the morning. Snow levels below 7000 feet. Chance of precipitation is 10%. Partly cloudy. Snow levels below 7000 feet. Chance of precipitation is 0%. Sunny. Snow levels below 7000 feet. Chance of precipitation is 0%.
Temperatures: 25 to 30. deg. F. 10 to 15. deg. F. 30 to 35. deg. F.
Mid Slope Winds: East around 15 mph with gusts to 30 mph. East around 15 mph in the evening becoming light. Gusts up to 30 mph. Light winds.
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. Slight chance of snow in the morning. Snow levels below 7000 feet. Chance of precipitation is 15%. Mostly cloudy then becoming partly cloudy. Snow levels below 7000 feet. Chance of precipitation is 0%. Sunny. Snow levels below 7000 feet. Chance of precipitation is 0%.
Temperatures: 21 to 26. deg. F. 9 to 14. deg. F. 28 to 33. deg. F.
Ridge Top Winds: East 15 to 30 mph with gusts to 50 mph. East 15 to 30 mph with gusts to 40 mph. East 15 to 25 mph.
Expected snowfall: No accumulation. | SWE = trace amounts. 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