THIS AVALANCHE ADVISORY EXPIRED ON December 19, 2015 @ 7:13 am
Avalanche Advisory published on December 18, 2015 @ 7:13 am
Issued by George Halcom - Payette Avalanche Center
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Today, the avalanche danger is CONSIDERABLE in the PAC advisory area. A WINTER STORM WARNING is in effect: a warm front along with heavy snow, and strong winds came in last night and will continue through tonight. This new snow will be challenged to bond to the older cold snow, and we may see some upside down, punchy, dangerous conditions today? Careful snowpack evaluation, cautious routefinding, and conservative decision making will be essential while traveling in avalanche terrain!

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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Strong winds gusting out of the South, Southwest upwards of 43 MPH have been pushing 6-12" of new snow into North, and North East aspects creating fresh wind slab hazard. Older wind slabs may still be found on all aspects. 

Avalanche Problem 2: Persistent Slab
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Pockets of buried surface hoar may exist in areas that were protected fron the wind. Brief cold clear conditions this past week have formed surface hoar that has been buried at two depths under a foot of snow. The Surface Hoar crystals that we noticed yesterday in a pit outside Tamarack, in Wildwood bowl came out in our stability test, after noticing it with the bare eye. The new snow, andwarmer temperaturesover the next 24 hours should help stabilize/ breakdown the buried surface hoar.

Avalanche Problem 3: Storm Slab
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Up to 2 feet of new snow is going to fall by the end of this winter storm warning this evening. The snow over the last 24 hours has come in quite a bit warmer, and heavier. This snow will be challenged to bond to the older cold snow, and we may see some upside down, punchy, dangerous conditions today?

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Friday Friday Night Saturday
Weather: Snow before 11am, then rain and snow. Chance of precipitation is 100%. Total daytime snow accumulation of 3 to 7 inches possible. Snow. Low around 19. Breezy, with a south southwest wind 18 to 23 mph. Chance of precipitation is 100%. New snow accumulation of 5 to 9 inches possible. Snow. Temperature rising to near 31 by 9am, then falling to around 21 during the remainder of the day. South southwest wind 5 to 9 mph becoming calm. Chance of precipitation is 100%. New snow accumulation of 1 to 3 inches possible.
Temperatures: High near 32 deg. F. Low of 27 deg. F. high of 21 deg. F.
Wind direction: south southwest south southwest Soutwest
Wind speed: 43 mph 18-23 MPH 5-9 MPH becoming calm
Expected snowfall: 3 to 7 inches possible in. 5-9 in. 1-3 in.
Granite Mountain at 7700 feet.
  Friday Friday Night Saturday
Weather: Snow. High near 28. Windy, with a south southwest wind 22 to 30 mph, with gusts as high as 40 mph. Chance of precipitation is 100%. Total daytime snow accumulation of 6 to 10 inches possible. Snow. Low around 20. Breezy, with a south wind 18 to 23 mph, with gusts as high as 32 mph. Chance of precipitation is 100%. New snow accumulation of 5 to 9 inches possible. Snow. High near 28. Southwest wind 13 to 18 mph decreasing to 5 to 10 mph in the afternoon. Chance of precipitation is 100%. New snow accumulation of 2 to 4 inches possible.
Temperatures: High near 28 deg. F. Low of 20 deg. F. High near 28 deg. F.
Wind direction: South, South West South West
Wind speed: 22-40 MPH 18-32 MPH 3-5
Expected snowfall: 6-10 in. 5-9 in. 2-4 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.