THIS AVALANCHE ADVISORY EXPIRED ON December 14, 2015 @ 7:00 am
Avalanche Advisory published on December 13, 2015 @ 7:00 am
Issued by Dave Bingaman - Payette Avalanche Center
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Increasing avalanche hazard today with over a foot of snow in the last 24 hours. Expect Considerable hazard in wind loaded terrain. Skiers and Snowmobilers are likely to trigger wind slabs on slopes over, or approaching 35 degrees on mid to upper elevation E- NW slopes. On protected slopes you may also trigger smaller slabs where new snow rests on last week's rain crust. The avalanche hazard will increase through the day with heavy snowfall, and increasing winds.

How to read the advisory


  • Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Wind Slab
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The new snow combined with winds out of the South-Southwest has formed wind slabs in higher elevation  E through NW facing terrain. Expect to see crossloading in gullies or other concavities on East and West facing slopes.Winds ramped up last night so yesterday's isolated slabs will be more widespread and gaining depth.  Winds will be shifting  to the West and Northwest this afternoon so expect to see additional wind slab formation on multiple aspects by tomorrow.

Avalanche Problem 2: Storm Slab
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In the  mid to upper evelvations the snow from the last 48 hours could be triggered within the new snow layers or down to the stout rain crust. With 12-20 inches of new snow over the last few days it will be possible to find storm slabs on steeper, wind protected terrain. Additional heavy snowfall and increasing temperatures this morning will add to the problem.

advisory discussion

Mountains will see additional snowfall of up to 13 inches today with heavy snow at times. Temps will increase slightly this morning and through the day then fall as a cold front enters our area this afternoon. Winds are the wild card today, throughout the advisory area upper elevations may see gusts in excess of 40 mph today. Cooler temperatures are in store for tomorrow with wind chills making it feel even colder.

weather

Snow. High near 29. Breezy, with a south southwest wind 15 to 24 mph becoming west northwest in the afternoon. Winds could gust as high as 33 mph. Chance of precipitation is 100%. New snow accumulation of 9 to 13 inches possible in the upper elevations.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Sunday Sunday Night Monday
Weather: Snow. High near 33. South wind 6 to 9 mph becoming west northwest in the afternoon. Winds could gust as high as 20 mph. Chance of precipitation is 100%. Total daytime snow accumulation of 3 to 7 inches possible. Snow showers, mainly before 11pm. Low around 22. North northwest wind 5 to 7 mph. Chance of precipitation is 90%. New snow accumulation of around an inch possible. A 20 percent chance of snow showers. Cloudy, with a high near 29. North northwest wind 6 to 10 mph, with gusts as high as 20 mph.
Temperatures: 32 deg. F. 22 deg. F. 29 deg. F.
Wind direction: S shifting to W then NW later today N/NW N/NW
Wind speed: 6-9 gusting to 20 5-7 6-10 gusting to 20
Expected snowfall: 3-7 in. 1 in. Trace in.
Granite Mountain at 7700 feet.
  Sunday Sunday Night Monday
Weather: Snow. High near 29. Breezy, with a south southwest wind 15 to 24 mph becoming west northwest in the afternoon. Winds could gust as high as 33 mph. Chance of precipitation is 100%. New snow accumulation of 9 to 13 inches possible. Snow showers. Low around 19. North northwest wind 8 to 16 mph. Chance of precipitation is 100%. New snow accumulation of 1 to 3 inches possible. A 40 percent chance of snow showers. Cloudy, with a high near 22. Blustery, with a north wind 15 to 24 mph, with gusts as high as 37 mph. New snow accumulation of less than one inch possible.
Temperatures: 29 deg. F. 19 deg. F. 22 deg. F.
Wind direction: S/SW shifting to W the NW this afternoon. N/NW N
Wind speed: 15-24 gusting to 33 8-16 15-24 gusting to 37
Expected snowfall: 9-13 in. 1-3 in. 1 in.
Disclaimer

This avalanche advisory is provided through a partnership between the Payette National Forest and the Payette Avalanche Center. This advisory covers the West Central Mountains between Hard Butte on the north and Council Mountain on the south. 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 at midnight on the posted day unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.