THIS AVALANCHE FORECAST EXPIRED ON December 1, 2018 @ 6:42 am
Avalanche Forecast published on November 30, 2018 @ 6:42 am
Issued by Brandon Schwartz - Tahoe National Forest

Areas of MODERATE avalanche danger exist near treeline and above treeline due to recently formed wind slabs. Below treeline, avalanche danger is LOW. Avalanche danger is expected to increase on Saturday at all elevations.

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 large enough to bury a person remain possible due to recent new snow and SW to W winds. The vast majority of wind slabs will be found near treeline and above treeline on NW-N-NE-E-SE aspects. Wind slabs will exist to a lesser degree on other aspects and in isolated wind exposed areas below treeline. A person traveling a wind loaded slope or cornice fall are the most likely triggers for avalanches today.

Exercise caution in areas with signs of recently wind drifted snow, especially adjacent to or below cornices, wind pillows, or wind textured snow surfaces.

recent observations
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* A small (size D1) snowboarder triggered (intentional) wind slab avalanche occurred yesterday on the East Ridge of Relay Peak (Mount Rose area) near treeline on a NE aspect, 32 degree slope.

* A small (size D1) skier triggered storm slab avalanche occurred yesterday on Andesite Peak (Donner Summit area) at treeline on a NE aspect, 40 degree slope.

* Observations made and received yesterday from Castle Peak (Donner Summit area), Forestdale Divide (South side Carson Pass area), and Tamarack Peak (Mount Rose area) revealed moderate to high intensity wind loading near and above treeline. On Castle Peak, cornices were building rapidly and collapsed easily. Minor cracking was observed around the edges of wind slabs. On Tamarack Peak, minor snow surface cracking was reported below treeline.

* Shallow snow cover remains in some areas. The deepest snowpack exists along the Sierra Crest above 7,500'.

Weather and CURRENT CONDITIONS
weather summary

A break between storm systems will occur today with mostly cloudy skies,  moderate speed ridgetop winds out of the SW to W, and the possibility of occasional light snow showers. The next storm system is expected to arrive late tonight or early tomorrow morning bringing additional snowfall, decreasing air temperatures, and ongoing SW winds.

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 22 to 27 deg. F.
Max. temperature: 27 to 32 deg. F.
Average ridgetop wind direction: SW
Average ridgetop wind speed: 47 mph
Maximum ridgetop wind gust: 83 mph
New snowfall: 10 to 17 inches
Total snow depth: 28 to 32 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Friday Friday Night Saturday
Weather: Mostly cloudy. Slight chance snow showers. Snow levels below 7000 feet. Chance of precipitation is 20%. Mostly cloudy. Snow likely after midnight. Snow levels below 7000 feet. Chance of precipitation is 70%. Cloudy. Snow in the morning, then widespread snow showers in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 100%.
Temperatures: 28 to 33. deg. F. 18 to 24. deg. F. 24 to 29. deg. F.
Mid Slope Winds: West 10 to 15 mph with gusts to 25 mph. Southwest 10 to 15 mph increasing to 15 to 25 mph with gusts up to 35 mph after midnight. Southwest 15 to 25 mph. Gusts up to 45 mph decreasing to 35 mph in the afternoon.
Expected snowfall: 20% probability up to 1 inch. 80% probability no accumulation. | SWE = less than 0.10 inch. 60% probability up to 1 inch. 40% probability of 1 to 3 inches. | SWE = less than 0.10 inch. 80% probability of 6 to 10 inches. 20% probability of 10 to 14 inches. | SWE = 0.50-0.80 inch.
For 8000 ft. to 9000 ft.
Friday Friday Night Saturday
Weather: Mostly cloudy. A chance of snow showers. Snow levels below 7000 feet. Chance of precipitation is 25%. Mostly cloudy. Snow likely after midnight. Snow levels below 7000 feet. Chance of precipitation is 70%. Cloudy. Snow in the morning, then widespread snow showers in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 100%.
Temperatures: 23 to 28. deg. F. 16 to 24. deg. F. 19 to 24. deg. F.
Ridge Top Winds: West 15 to 25 mph with gusts to 40 mph. Southwest 15 to 25 mph with gusts to 40 mph increasing to 20 to 35 mph with gusts to 60 mph after midnight. Southwest 25 to 40 mph shifting to the west 20 to 30 mph in the afternoon. Gusts up to 75 mph.
Expected snowfall: 20% probability up to 1 inch. 80% probability no accumulation. | SWE = less than 0.10 inch. 60% probability up to 2 inches. 40% probability of 2 to 4 inches. | SWE = less than 0.10 inch. 80% probability of 8 to 14 inches. 20% probability of 12 to 18 inches. | SWE = 0.75-1.2 inches.
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