THIS AVALANCHE ADVISORY EXPIRED ON December 22, 2016 @ 6:50 am
Avalanche Advisory published on December 21, 2016 @ 6:50 am
Issued by Dave Bingaman - Payette Avalanche Center
bottom line

The avalanche danger is Considerable this morning in wind loaded  Northern aspects above 7,000 feet. Below 7,000 feet, the avalanche danger is Moderate.

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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Yesterday we witnessed the forming of wind slabs on North and Nothwest aspects due to strong to intense SSW winds.

Older wind slabs from recent North wids have slowly stiffened and become harder to trigger, but are still present. 

To travel safely today, it is going to be important to keep your eyes out for obvious signs of wind loaded slopes. Be on the lookout for wind scouring and loading (lens shaped slabs), keep an eye out for cracking of surface snow, and make terrain decisions that (in a worst case scenario) would not cause you to be taken over cliffs or into a terrain trap.

Avalanche Problem 2: Storm Slab
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The new snow is trying to bond to the old snow. Yesterday we were getting moderate results on the new snow interface. While traveling in avalanche terrain today it will be essential to do lots of quick hand pits to assess how the new snow is bonding with the old snow surface. Is it easy to pull new snow off in a soft and cohesive slab? Does that new soft slab shear easily from the old snow surface? 

advisory discussion

We have a number of great beginner avalanche classes coming up. Be sure to check out 'local classes' under the Education tab at the top of the forecast page. If already have the basics down and are ready to take your Level One, do it. Make staying safe while playing in avalanche terrain a New Year's Resolution!

 

***Also, we apologize for the recent number of e-mails that people may be receiving from us due to our sever error, we hope to have this fixed soon.

recent observations

No new natural or human caused avalanches have been seen or reported.

Yesterday, we toured out near Summit Lake, Sesesch Summit Area. South West winds were strong to intense (40MPH) at ridgetop, allowing for transport of the new snow into Northern aspects. Althougght he majority of the winds were out of the SW yesterday, we noticed gusts out of the North also. Wind slabs, old and new were peeling off with the weight of  a skier. We dug a test pit on  North West aspect at 8200 feet. we did find some graupel and crusts within the snowpack. The most notable failure was in the new snow interface CTM-15. Faceted snow was present above and below crusts in the lower pack, but are rounding/strengthening, and did not come out in our stability tests.

 

 

weather

As of 6 am it is 13 degrees at the summit of Brundage this morning, and 0 degrees in McCall. We will see areas of fog this morning with sunny skies taking over for the next 24 hours. Daytime high temperatures will climb to 23 degrees in McCall, and the summit of Brundage will also see a high temperature of 23 degrees. Winds will be light (5-8MPH) out of the North/North East, becoming calm.

Our next significant weather system will impact the PAC advisory area Friday night into Saturday.

 

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Wednesday Wednesday Night Thursday
Weather: Areas of fog before 11am. Otherwise, sunny, with a high near 23. Wind chill values between -9 and 1. East northeast wind around 5 mph becoming calm in the morning. Areas of fog. Otherwise, mostly clear, with a low around -4. Wind chill values between -8 and -13. Calm wind becoming southeast around 5 mph. Areas of fog before 11am. Otherwise, increasing clouds, with a high near 20. Wind chill values between -6 and -16. South southeast wind around 6 mph.
Temperatures: High 23 deg. F. Low -4 deg. F. High 20 deg. F.
Wind direction: East North East South East South-South East
Wind speed: 5 Mph-Calm 5 MPH 6MPH
Expected snowfall: 0 in. 0 in. 0 in.
Granite Mountain at 7700 feet.
  Wednesday Wednesday Night Thursday
Weather: Sunny, with a high near 22. Wind chill values between -3 and 7. North wind 5 to 7 mph becoming calm. Mostly clear, with a low around 3. Wind chill values between -7 and -17. Breezy, with a south wind 8 to 13 mph increasing to 15 to 20 mph after midnight. Increasing clouds, with a high near 21. Wind chill values between -9 and -19. Breezy, with a south wind 21 to 24 mph, with gusts as high as 33 mph.
Temperatures: High 22 deg. F. Low 3 deg. F. High 21 deg. F.
Wind direction: North-Calm South South
Wind speed: 26 to 34 gusting 46 8 to 20 21-33
Expected snowfall: 0 in. 0 in. 0 in.
Disclaimer

This avalanche advisory is provided through a partnership between the Payette National Forest and the Friends of 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.