THIS AVALANCHE ADVISORY EXPIRED ON March 11, 2016 @ 7:18 am
Avalanche Advisory published on March 10, 2016 @ 7:18 am
Issued by Dave Bingaman - Payette Avalanche Center
bottom line

The Avalanche Danger is Considerable on slopes over 35 degrees. A combination of slick crusts, wet snow and rain in the lower elevations combined with strong South winds will make skier triggered avalanches likely. Windloaded/crossloaded E, NE, N, NW and W aspects should be approached with caution. These slabs will continue to grow throughout the day today with strong winds continuing tonight. Loose/wet and shallow wet slab avalanches should be anticipated on on all slopes over 35 degrees today.

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

Winds out of the South/ Southwest created isolated wind slabs that we were still encountering yesterday.  With strong winds yesterday afternoon and through the night combined with some wet snow, expect the windslab problem to have grown significantly overnight. Some of these slabs will have formed on a slick rain crust from last weekend's rain event which will increase the hazard and likelihood of triggering the slab. Steep leeward, windloaded slopes should be avoided or only approached after careful snowpack assessment. Crossloading will likely have occurred as well on East and West aspects as the winds were predominantly out of the South.  Today and tonight winds are expected to remain strong with gusts possibly reaching 50 MPH today.  Expect the windslab problem to continue to increase as the slabs get thicker. Cracking, hollow or drummy sounds, sculpting of the snow surface, thick pillows, and thin spots are all clues that should help you recognize wind slab problems. 

Avalanche Problem 2: Loose Wet
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

The rain line rose Sunday to above 7,000 feet. The new snow (4-6") is resting on a crust (below that crust, below 7,500 ft the snow is still mostly saturated)  that formed last weekend.  The added stress of rain and or wet snow will increase the possibility of loose/wet avalanches on  slopes over 35 degrees today.  As the new snow piles up on the old crust, wet storm slabs will likely form adding to the avalanche problem. Know what you are riding on, take the time to check the snowpack before committing to any steep slope over the next few days.  

This photo is of a skier triggered loose/wet avalanche near Tamarack Resort that occurred on Tuesday. Thanks for taking the time to fill out our report form!

advisory discussion

Our condolences go out to the Wallowa Avalanche Center Friends and Family. Kip Rand, the director of the center was killed in an avalanche on Tuesday while skiing with a friend on his day off. Information can be found at: http://www.wallowaavalanchecenter.org/news/1954

 

recent observations

Over the last few days, we have seen a lot of good sized loose/wet avalanches on East Aspects running on a combination of colder snow below or even down to last weekend's rain crust.  We were in the 20 Mile Drainage yesterday and saw a couple more on steep terrain. Most were starting as point releases off and spreading out and entraining a good amount of the loose snow above the rain crust from last weekend.  Expect the crust to continue to play a role in the avalanche conditions over the next few day until the new snow has a change to bond to it.  Wind slabs on crusts in the leeward terrain are going to be growing fast with strong S winds and new snow through the next few days.

 

weather

Wind and Rain or Wet Snow. This storm is expected to bring between .5 and 1 inch of water to the West Central Mountains. Freezing lines will be between 6000 and 7500 feet over the next 24 hours with a cooldown expected Saturday.  With high snowlines, snowfall totals are going to be hard to predict, upper elevations are expected to get 3-9 inches through tomorrow afternoon. The real story is the moisture plume and the cold front expected on Saturday evening...if the temps stay low, Sunday looks like a powder day with accumulations between 5 and 9 inches.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Thursday Thursday Night Friday
Weather: Showers. High near 43. South southeast wind 10 to 13 mph. Chance of precipitation is 80%. Showers. Low around 34. South southeast wind 6 to 9 mph. Chance of precipitation is 80%. Showers. High near 44. South southeast wind 3 to 8 mph. Chance of precipitation is 80%.
Temperatures: 43 deg. F. 34 deg. F. 44 deg. F.
Wind direction: S/SE S/SE S/SE
Wind speed: 10-13 6-9 3-8
Expected snowfall: Rain in. Rain in. Rain in.
Granite Mountain at 7700 feet.
  Thursday Thursday Night Friday
Weather: Snow showers. High near 41. Windy, with a south wind 29 to 36 mph, with gusts as high as 50 mph. Chance of precipitation is 100%. Total daytime snow accumulation of 1 to 3 inches possible. Rain and snow showers, becoming all snow after 11pm. Low around 30. Breezy, with a south southwest wind 15 to 25 mph, with gusts as high as 37 mph. Chance of precipitation is 100%. New snow accumulation of 1 to 3 inches possible. Snow showers likely. Cloudy, with a high near 40. South southeast wind 11 to 14 mph. Chance of precipitation is 70%. New snow accumulation of 1 to 2 inches possible.
Temperatures: 41 deg. F. 30 deg. F. 40 deg. F.
Wind direction: South S/SW S/SE
Wind speed: 29-36, Gusts to 50 15-25, Gusts to 37 11-14
Expected snowfall: 1-3 in. 1-3 in. 1-2 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.