THIS AVALANCHE ADVISORY EXPIRED ON January 17, 2016 @ 6:50 am
Avalanche Advisory published on January 16, 2016 @ 6:50 am
Issued by George Halcom - Payette Avalanche Center
bottom line

The avalanche danger is CONSIDERABLE above 7,000 feet. Wind loaded slopes, and slopes that were protected from the wind are harboring a buried weak layer. A foot of snow since Wednesday and moderate to strong winds created slabs, and are sitting on different surfaces on all leeward slopes. If traveling above 7,000 feet human caused avalanches are likely. Below 7,000 feet the avalanche danger is MODERATE due to wind slabs, and human triggered avalanches are possible.

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 winds howled during the last storm that caused widespread natural avalanches early Thursday morning. Be on the look out for wind slabs in likely and unlikely places (below cliffs, cross-loaded slopes). These new wind slabs are going to be reactive on all leeward (downwind) aspects over 30 degrees that have obvious signs of wind loading (smooth rounded pillow like snow surface) and could range from 6 inches to 3 feet in depth. These wind slabs could be located mid-slope on steep open faces. This will allow you to get half way down a slope before getting into trouble. 

Avalanche Problem 2: Persistent Slab
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Surface Hoar, and Near Surface Facets that formed during our last extended cool, dry weather are now buried about 33CM/ 1 foot down. Natural avalanches went Thursday morning on many wind loaded Northern, Eastern, and South Eastern slopes...this persistent weak layer has the potential to linger for a while in our snowpack, and is a very common factor in avalanche fatalaties...take the time to dig, and evaluate every slope above 30 degrees, and stay far from the bottom,or run-outof steep slopes!

Avalanche Problem 3: Loose Dry
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This foot of new, dry, cold snow has the potential to run with you, or sluff. Pay attention to your sluff it can knock you off your feet, and put you into places you would rather not be.

advisory discussion

It is game on for avalanche conditions in the backcountry! Slopes over 30 degrees warrent respect and patience. With 12 inches of new snow and the perfect making of an avalanche (surface hoar/facets with a new slab on top) these are prime condintions to get into trouble if you do not carefully evaluate the snowpack and make conservative decisions. Keep to lower angle slopes in sheltered terrain today and enjoy the cold powder.

recent observations

Yesterday, we toured the Rapid Creek area East of Jug Mountain and found evidence of Natural avalanches large enough to bury or kill a person on a couple of SE aspects, and more buried surface hoar 45 cm down, in our pits that scored moderately in tests, and a crust combo on a SE aspect.

Thursday we toured a large chunk of the advisory area, and we were not suprised to find fresh evidence of natural avalanches on mainly Northern aspects that went on a layer of buried surface hoar (33CM Down) that formed during our cool dry spell. The winds overloaded this layer, and it is still buried, waiting for a trigger in many other places. More snow will ramp up the danger on this persistant weak layer. We had simiar reports from Tamarack, but also on South aspects there. 

weather

Snow showers will be the theme of the day with 3-5 inches forecasted for the higher elevations, and 1-3 inches forecasted for McCall. Winds will be out of the West/Southwest around 17 MPH up high, and around 6 MPH this afternoon in McCall.

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 29. Calm wind becoming south southeast around 6 mph in the afternoon. Chance of precipitation is 100%. New snow accumulation of 1 to 3 inches possible Snow showers likely, mainly before 11pm. Cloudy, with a low around 23. Light southeast wind. Chance of precipitation is 70%. New snow accumulation of less than one inch possible. Snow after 11am. High near 32. Calm wind becoming southeast around 5 mph in the afternoon. Chance of precipitation is 90%. New snow accumulation of 1 to 2 inches possible.
Temperatures: High 29 deg. F. Low 23 deg. F. High 32 deg. F.
Wind direction: SSE SE SE
Wind speed: 6 MPH Light 5MPH
Expected snowfall: 1-3 in. less than one in. 1-2 in.
Granite Mountain at 7700 feet.
  Saturday Saturday Night Sunday
Weather: Snow. High near 30. West southwest wind 14 to 17 mph. Chance of precipitation is 100%. New snow accumulation of 3 to 5 inches possible. Snow showers, mainly before 11pm. Low around 23. West northwest wind 8 to 16 mph. Chance of precipitation is 80%. New snow accumulation of 1 to 2 inches possible Snow, mainly after 11am. High near 32. Breezy, with a southwest wind 10 to 15 mph increasing to 17 to 22 mph in the afternoon. Chance of precipitation is 90%. New snow accumulation of 1 to 3 inches possible.
Temperatures: High 30 deg. F. Low 23 deg. F. High 32 deg. F.
Wind direction: WSW WNW SW
Wind speed: 14-17 MPH 8-16 MPH 15-22 MPH
Expected snowfall: 3-5 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.