THIS AVALANCHE ADVISORY EXPIRED ON December 20, 2015 @ 6:49 am
Avalanche Advisory published on December 19, 2015 @ 6:49 am
Issued by George Halcom - Payette Avalanche Center
bottom line

The avalanche danger remains CONSIDERABLE in the PAC advisory area. The storm cycle over the last 48 hours brought in over a foot of warm, heavy snow, and strong winds out of the South, Southwest. Temperatures will fall today as we switch back to a cooling trend, and light snowfall. Careful snowpack evaluation, cautious routefinding, and conservative decision making will be essential while traveling in avalanche terrain, especially wind loaded aspects!

How to read the advisory


  • Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Wind Slab
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Strong winds gusting out of the South, Southwest upwards of 43 MPH have been pushing over a foot 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
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Pockets of buried surface hoar may exist in areas that were protected from 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, and cooler temperatures over the weekend should help stabilize/ breakdown the buried surface hoar.

Avalanche Problem 3: Storm Slab
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Up to 2 feet of new snow over the last 24 hours has come in quite a bit warmer, and heavier. This snow will settle fast, and should  bond to the older cold snow. Yesterday, we had some upside down, punchy, challenging trailbreaking conditions up the Lick Creek drainage.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Saturday Saturday Night Sunday
Weather: Snow. High near 32. Calm wind becoming south southwest around 6 mph in the afternoon. Chance of precipitation is 90%. Total daytime snow accumulation of 1 to 3 inches possible. Snow showers likely, mainly before 11pm. Cloudy, with a low around 16. Calm wind becoming south around 5 mph after midnight. Chance of precipitation is 60%. New snow accumulation of less than one inch possible. Snow showers after 11am. High near 25. South wind 6 to 14 mph. Chance of precipitation is 80%. New snow accumulation of around an inch possible.
Temperatures: High near 32 deg. F. Low of 16 deg. F. high of 25 deg. F.
Wind direction: Calm becoming south southwest Calm becoming South South
Wind speed: 6 mph 5 MPH 6-14 MPH
Expected snowfall: 1 to 3 inches possible in. Less than an inch in. 1 in.
Granite Mountain at 7700 feet.
  Saturday Saturday Night Sunday
Weather: Snow. Temperature falling to around 23 by 4pm. South southwest wind 14 to 17 mph. Chance of precipitation is 90%. Total daytime snow accumulation of 2 to 4 inches possible. Snow showers likely, mainly before 11pm. Cloudy, with a low around 13. South southwest wind 5 to 9 mph. Chance of precipitation is 70%. New snow accumulation of 1 to 2 inches possible. Snow showers, mainly after 11am. High near 22. Wind chill values between -5 and 4. Breezy, with a south wind 11 to 16 mph increasing to 19 to 24 mph in the afternoon. Chance of precipitation is 80%. New snow accumulation of 1 to 3 inches possible.
Temperatures: High near 23 deg. F. Low of 13 deg. F. High near 22 deg. F.
Wind direction: South, South West South,Southwest South
Wind speed: 14-17 MPH 5-9 MPH 11-16
Expected snowfall: 2-4 in. 1-2 in. 1-3 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.