THIS AVALANCHE ADVISORY EXPIRED ON January 7, 2016 @ 5:51 am
Avalanche Advisory published on January 6, 2016 @ 5:51 am
Issued by Dave Bingaman - Payette Avalanche Center
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The Avalanche Hazard remains MODERATE at upper elevations, above 7,000 feet where the possibility of triggering a wind slab in steep wind loaded terrain still exists. These wind slabs are scattered near ridge tops and in other terrain features that caught last week's blowing snow, and recent snow this week.  Exercise caution in all steep, consequential terrain...

In non-wind loaded terrain, below 7,000 feet, Avalanches are possible but not likely: stability is good and the Avalanche Hazard is LOW.

How to read the advisory


  • Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Wind Slab
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The possibility of triggering wind slabs is still a concern in the upper elevations near ridge tops and in a few pockets where blowing snow can accumulate.  A fresh crop of shallow wind slabs have formed since Sunday morning. Yesterday we were on the Six Mile Ridge of Granite Mt. at our weather station and found areas with significant loading and drifting near the ridgetop.  Over the last few days we have also observed cracking around  and in front of our skis in these areas. You will find these new and some old wind slabs mostly on the north half of the compass and scattered on east and west aspects where cross loading has occurred. Be weary of cross loaded slopes in the upper elevations where shifting winds have caused inconsistent loading. 

Most of these wind affected areas are going to be pretty obvious as a density change or an area of stiffer snow in the otherwise soft snow around them. Look for them below cornices, on steep rollovers, and in gullies or small depressions on the slope.You can also see what the wind has been doing, look for drifts, spines or areas of sculpted/scoured snow.  These visual clues are pretty obvious if you can see the terrain around you.  The wind slabs that we have been finding this week are shallow in most areas and only reactive on steeper terrain. Keep in mind that wind slabs are commonly triggered from thin areas, or edges of the slab.

recent observations

Snowmobiles are getting into non-motorized areas...check the Winter Travel Map on closures before you head out. Remember that the Granite Mt. closure goes into effect on 1/15 also, please respect non-motorized closures in the area.

Skiers and riders are getting into some of our more consequential terrain...make sure that you have an escape route planned if something goes wrong: if you do trigger a wind slab in a steep, wind loaded start zone, you may take a long ride into rocks, or possibly off a cliff. Use good travel practices when you are in steeper terrain and make sure that everyone in your group is carrying avalanche rescue gear.

weather

Expect light snow through the day today with 1-2 inches of new snow tonight. Warm temperatures will remain through tomorrow.  Most of the moisture from will be passing to the south of the West Central Mountains as a Pacific Storm tracks through the Southwest and Central Nevada.  Look for decreasing temperatures ahead of another high pressure that will enter the Northwest over the weekend.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Wednesday Wednesday Night Thursday
Weather: Snow, chance of precipitation is 80%. Total nighttime snow accumulation of less than a half inch possible. Snow before 11am, then rain and snow. Patchy fog before 11am. Chance of precipitation is 80%. New snow accumulation of around an inch possible. Snow showers likely, mainly before 11pm. Cloudy with a chance of precipitation is 60%. New snow accumulation of less than one inch possible.
Temperatures: 28 deg. F. 32 deg. F. 21 deg. F.
Wind direction: S S S
Wind speed: Calm Calm Calm
Expected snowfall: 1/2 in. 1 in. Trace in.
Granite Mountain at 7700 feet.
  Wednesday Wednesday Night Thursday
Weather: Snow, chance of precipitation is 80%. Total nighttime snow accumulation of less than one inch possible. Snow, chance of precipitation is 80%. New snow accumulation of 1 to 2 inches possible. Cloudy, with a 50 percent chance of snow showers.
Temperatures: 24 deg. F. 31 deg. F. 21 deg. F.
Wind direction: S S S
Wind speed: Around 10 7-10 5 becoming light and variable.
Expected snowfall: 1 in. 1-2 in. trace 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.