THIS AVALANCHE ADVISORY EXPIRED ON February 9, 2017 @ 6:56 am
Avalanche Advisory published on February 8, 2017 @ 6:56 am
Issued by George Halcom - Payette Avalanche Center
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The avalanche danger is Considerable above 6000 feet due to human triggered avalanches being likely in wind exposed terrain. Over the last 24 hours we have seen moderate to high winds which created wind slabs that are widespread. The danger is Moderate below 6000 feet where wind slabs are less widespread but storm slab human triggered avalanches are possible in steep sheltered terrain.  This evening as temperatures and snow levels rise, the avalanche hazard will rise along with it.

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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We have received up to two feet of new snow in the last few days in the upper elevations. The new snow, combined with moderate to strong winds out of the south-southwest have created widespread wind slabs.

Due to the erratic and moderate to high winds, wind slabs could potentially be found on what is normally a sheltered slope, even in the middle elevations. Be weary near ridges and in typical cross-loaded slopes in exposed terrain, or any slope that has small cornices or pillowy looking snow.  Some areas may only have thin and tender slabs that are easy to manage, while other slopes the slabs may be up to 3 feet thick. While we wait for these slabs to heal, I would continue to avoid traveling on or under any wind affected terrain.  If you see cracks shooting out as you are moving or encounter large drifts or stiff snow, move to more sheltered and/or low angle terrain.

 

Avalanche Problem 2: Storm Slab
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In areas that were not affected by the winds over the last few days, it could be possible to trigger a storm slab. While storm slabs stabilize rather quickly by definition, some instabilities can still be found within the storm snow layers where the hardeness (density) of snow layer changes. Because of this, I would stay off of steep slopes today, even if they are small and/or show no signs of wind slab.

 

advisory discussion

Snowmobiler/Snowbiker Travel Restrictions:  a quick reminder that the Granite Mountain Area Closure is now in effect, please respect Snowcats operating in this  and nearby areas.  In addition there are other areas on the Payette National Forest that are CLOSED to snowmobile traffic including Jughandle Mt east of Jug Meadows, Lick Creek/Lake Fork Drainage (on the right side of the road as you are traveling up canyon), and the area north of Brundage Mt Ski area to junction "V" and along the east side of Brundage and Sergeants' Mts. with the exception of the Lookout Rd( junction "S").  Please respect these closures and other users recreating in them.  Winter Travel Map(East side). You can download the map to the AVENZA app on your phone, and know your exact location while you are out riding.

The Friends of the Payette Avalanche Center (FPAC) needs YOU! We are in desperate need of more user support and financial assistance. The avalanche forecast is not a guaranteed service, and is in jeopardy of dwindling down to only a couple of days a week in the near future. Please help if you can by clicking the DONATE tab above. If you value this life saving information, make a donation or help the FPAC in raising funds for the future.

recent observations

Yesterday, near Secesh Summit the wind effect was obvious as seen below in this picture.

 

 

 

 

 

 

 

 

 

Yesterday we also got some old news:  local snomobilers reported triggerring slabs up to 3 feet deep on Monday on a Northeast aspect around 7,000 feet somewhere on the Payette National Forest.

We have been hearing of avalanches being triggered in the advisory area. If you see or trigger an avalanche please let us know as soon as possible. When it comes to staying safe in the mountains, we are all in this together. Email us at: forecast@payetteavalanche.org

Just sending us a picture and description of the location (aspect, elevation, slope angle), helps us a ton!

 

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 19 deg. F.
Max. temperature in the last 24 hours: 21 deg. F.
Average wind direction during the last 24 hours: NA
Average wind speed during the last 24 hours: NA mph
Maximum wind gust in the last 24 hours: NA mph
New snowfall in the last 24 hours: NA inches
Total snow depth: NA inches
weather

Around an inch or two of new snow fell overnight, and the southwest winds have come down from the 20's to the teens this morning.

Today in the upper elevations we are forecasted for snow, mainly after 11am. High near 29. Breezy, with a southwest wind 16 to 23 mph. Chance of precipitation is 100%. Total daytime snow accumulation of 3 to 5 inches possible.

Snow levels will rise to 7000-8000 feet MSL by sunrise Thursday, and stay there Thursday with highest levels in south-central Idaho. High temperatures today will be much like Tuesday, but little or no cooling is expected tonight, and then significantly warmer Thursday with highs in the 40s in the mountains and 45 to 55 in the valleys

LONG TERM...Thursday night through Wednesday. A very moist flow will continue to impact the area, especially the Idaho Central Mountains through Friday. By Friday evening into Saturday, the main trough axis will swing through, along with a cold front. The cold front is fairly dry, so once it moves through, that will begin a prolonged period of dry conditions. Models continue to show an upper level ridge setting up for Saturday through Wednesday. At this point, valleys are not expected to become inverted and cold, but rather mild and near normal with mostly clear skies.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Wednesday Wednesday Night Thursday
Weather: Snow, mainly after 11am. High near 35. South southeast wind 5 to 7 mph. Chance of precipitation is 100%. New snow accumulation of less than one inch possible. Rain and snow, becoming all rain after 11pm. Temperature rising to around 40 by 5am. South southeast wind 6 to 9 mph. Chance of precipitation is 100%. Little or no snow accumulation expected. Rain. High near 41. South southeast wind 10 to 17 mph. Chance of precipitation is 100%.
Temperatures: high 35 deg. F. low 40 deg. F. high 41 deg. F.
Wind direction: south-southeast south-southeast south-southeast
Wind speed: 5-7 6-9 10-17
Expected snowfall: less than one in. 0 in. 0 in.
Granite Mountain at 7700 feet.
  Wednesday Wednesday Night Thursday
Weather: Snow, mainly after 11am. High near 29. Breezy, with a south southwest wind 16 to 23 mph. Chance of precipitation is 100%. New snow accumulation of 3 to 5 inches possible. Snow. Temperature rising to around 38 by midnight. Windy, with a southwest wind 26 to 34 mph, with gusts as high as 46 mph. Chance of precipitation is 100%. New snow accumulation of 2 to 4 inches possible. Rain. High near 41. South southeast wind 10 to 17 mph. Chance of precipitation is 100%.
Temperatures: high 29 deg. F. low 38 deg. F. high 41 deg. F.
Wind direction: south-southwest southwest south-southeast
Wind speed: 16-23 26-34 10-17
Expected snowfall: 3-5 in. 2-4 in. 0 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.