THIS AVALANCHE ADVISORY EXPIRED ON February 17, 2016 @ 6:00 am
Avalanche Advisory published on February 16, 2016 @ 6:00 am
Issued by George Halcom - Payette Avalanche Center
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The avalanche danger is CONSIDERABLE today on solar aspects which will have the possibility of producing natural avalanches as the sun pokes through the clouds and heats an already warm snow surface.  Human triggered avalanches are possible on recent storm slabs (4-10 inches) resting on a slick melt/freeze crust. Northern aspects will have MODERATE avalanche danger.

How to read the advisory


  • Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Storm Slab
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With 7 inches over the last 48 hours in the high country be mindful of storm slabs above 7,000 feet. This new snow is sitting on a melt freeze crust from last weeks warm up, this is making for a easy sliding bed surface for the new snow.

Avalanche Problem 2: Wet Slab
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Solar aspects will have the possibility of producing natural avalanches, mainly point releases, as the sun pokes through the mostly cloudy skies today, and stresses a warm snow pack. Temperatures hoverd above freezing last night in the upper elevations, around 35 degrees, and we should see a high temperature of 40 degrees in the upper elevations.

Avalanche Problem 3: Persistent Slab
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Triggering a slab due to this weak layer has become more difficult over the last few days with the heat, but I would not let my guard down, We are still finding this weak layer in upper elevation wind protected terrain. Pit results and stability testing are pointing toward less likelihood of triggering, but if triggered we are still talking about a potentially unsurvivable hard slab avalanche. Take the time to carefully assess terrain choices on the north half of the compass today. Especially areas where the snow cover is thinner which allows the buried surface hoar to be closer to the surface, and in turn more reactive---especially for snowmachines. This is the same layer that was the cause of the fatal avalanche on January 31st. A persistent weak layer such as this is a low probablility, but HIGH CONSEQUENCE scenario. 

weather

 

For McCall this morning we should see some patchy dense fog before 11am. Otherwise, mostly cloudy through the day with a high near 42. Light south wind.

Up in the high country around 7600 feet on Granite Mtn, we should see A 30 percent chance of snow showers, mainly before 11am. Cloudy, with a high near 40 degrees. Southwest wind around 15 mph. New snow accumulation of less than a half inch possible. Wednesday looks to be quite windy: 49 MPH SW winds....be ready for power outages?

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Tuesday Tuesday Night Wednesday
Weather: Patchy dense fog before 11am. Otherwise, mostly cloudy, with a high near 42. Light south wind. Mostly cloudy, with a low around 28. Light east southeast wind. A 30 percent chance of showers after 11am. Mostly cloudy, with a high near 42. Calm wind becoming south southeast 5 to 8 mph in the afternoon.
Temperatures: 42 deg. F. 28 deg. F. 42 deg. F.
Wind direction: S ESE SSE
Wind speed: Light Light calm-5-8MPH
Expected snowfall: 0 in. 0 in. 0 in.
Granite Mountain at 7700 feet.
  Tuesday Tuesday Night Wednesday
Weather: A 30 percent chance of snow showers, mainly before 11am. Cloudy, with a high near 40. Southwest wind around 15 mph. New snow accumulation of less than a half inch possible. Mostly cloudy, with a low around 33. Southwest wind 14 to 16 mph. A 40 percent chance of snow showers after 11am. Mostly cloudy, with a high near 44. Windy, with a south southwest wind 17 to 22 mph increasing to 28 to 33 mph in the afternoon. Winds could gust as high as 49 mph. New snow accumulation of less than a half inch possible.
Temperatures: 40 deg. F. 33 deg. F. 44 deg. F.
Wind direction: SW SW SSW
Wind speed: 15 MPH 14-16 MPH 17-33MPH, Gusting to 49MPH
Expected snowfall: less than half in. 0 in. 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.