THIS AVALANCHE FORECAST EXPIRED ON November 30, 2018 @ 6:50 am
Avalanche Forecast published on November 29, 2018 @ 6:50 am
Issued by Steve Reynaud - Tahoe National Forest

High Avalanche Danger will exist today as heavy snowfall with gale force winds impact our forecast region.  Wind slab and storm slab avalanche problems will become very likely today in near treeline and above treeline terrain where previous snow cover existed.  Considerable Avalanche danger will exist in below treeline terrain at lower elevations with minimal previous snow cover.  Dangerous avalanche conditions will exist today, travel in avalanche terrain is not recommended.

4. High

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Above Treeline
Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.

4. High

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Near Treeline
Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.

3. Considerable

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Below Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
    Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
Avalanche Problem 1: Wind Slab
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Wind slabs will be very likely today due to high snowfall rates and gale force SW winds.  Wind slabs will be most likely on NW-N-NE-E-SE aspects in near and above treeline terrain.  Look for blowing snow, cornice formation, and wind pillow development.  Travel in or near avalanche terrain is not recommended. 

Early season conditions exist.  An avalanche of any size through rocks, bushes, and/or obstacles could have severe consequences.  Avoid steep wind loaded terrain and runout zones below avalanche terrain. 

Avalanche Problem 2: Storm Slab
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Storm slabs will become likely during peak snowfall rates throughout the day.  Storm slabs could exist on all aspects in near and below treeline terrain in areas that had existing snow cover.  Heavy snowfall rates of over 2'' an hour could overcome the bonding of the new storm snow.

Early season conditions exist.  An avalanche of any size through exposed rocks, bushes, and/or obstacles could have severe consequences.  Travel in and around avalanche terrain is not recommended today.    

recent observations
Submit Observations

* Observations from Castle Peak yesterday showed a well bonded snowpack with no layers of concern.  Cornices were building out on ridges in near treeline and above treeline terrain.  Most starting zones above 8000' had uniform coverage.

* Recent observations from the Carson Pass, Echo Summit, Donner Pass, and Mount Rose areas all indicate that the snowpack is in good condition to handle new snow loading in the vast majority of areas.

* The existing snowpack is mostly usable along the Sierra Crest above 7500'.  Below 7500' and along the Carson Range to the east, the snowpack is borderline usable.  Many obstacles like rocks, bushes, logs, and open water, still exist.

Weather and CURRENT CONDITIONS
weather summary

A winter storm warning is in effect until Friday morning at 4am.  6 to 10'' of new snow has fallen along the Sierra Crest above 7800' overnight with an expected 1 to 2' of snowfall for areas above 7000' today.  Higher amounts are expected along the Sierra Crest.  Strong to gale force SW winds have been in the 40 to 55mph range with gusts up to 80mph over ridges.  Snowfall is expected to increase into the morning and also in the afternoon hours.  A brief break in snowfall is expected Friday with another storm expected Friday night into Saturday.

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 30 deg. F.
Max. temperature: 36 deg. F.
Average ridgetop wind direction: SW
Average ridgetop wind speed: 30 to 55 mph
Maximum ridgetop wind gust: 80 mph
New snowfall: 5 to 10 inches
Total snow depth: 18 to 28 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Thursday Thursday Night Friday
Weather: Cloudy. Snow. Snow levels below 7000 feet. Chance of precipitation is 100%. Cloudy. Widespread snow showers. Snow levels below 7000 feet. Chance of precipitation is 80%. Mostly cloudy. Chance of snow showers. Snow levels below 7000 feet. Chance of precipitation is 35%.
Temperatures: 30 to 35. deg. F. 22 to 27. deg. F. 28 to 33. deg. F.
Mid Slope Winds: South 15 to 25 mph with gusts to 35 mph. Southwest 10 to 15 mph with gusts to 30 mph. West 10 to 15 mph with gusts to 30 mph.
Expected snowfall: 70% probability of 7 to 12 inches. 30% probability of 9 to 15 inches. | SWE = 0.65-1.10 inches. 70% probability of 2 to 5 inches. 30% probability of 4 to 7 inches. | SWE = 0.15-0.35 inch. Up to 1 inch. | SWE = less than 0.10 inch.
For 8000 ft. to 9000 ft.
Thursday Thursday Night Friday
Weather: Cloudy. Snow. Snow levels below 7000 feet. Chance of precipitation is 100%. Cloudy. Widespread snow showers. Snow levels below 7000 feet. Chance of precipitation is 80%. Mostly cloudy. Chance of snow showers. Snow levels below 7000 feet. Chance of precipitation is 40%.
Temperatures: 25 to 30. deg. F. 19 to 24. deg. F. 24 to 29. deg. F.
Ridge Top Winds: Southwest 30 to 45 mph with gusts to 85 mph decreasing to 20 to 30 mph with gusts to 65 mph in the afternoon. Southwest 15 to 25 mph. Gusts up to 50 mph decreasing to 35 mph after midnight. West 15 to 25 mph with gusts to 40 mph.
Expected snowfall: 70% probability of 11 to 17 inches. 30% probability of 12 to 20 inches. | SWE = 0.75-1.25 inches. 90% probability of 3 to 7 inches. 10% probability of 5 to 8 inches. | SWE = 0.15-0.40 inch. Up to 1 inch. | SWE = less than 0.10 inch.
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