THIS AVALANCHE ADVISORY EXPIRED ON February 7, 2017 @ 6:43 am
Avalanche Advisory published on February 6, 2017 @ 6:43 am
Issued by Kent May - Payette Avalanche Center
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The avalanche danger is HIGH above 6000 feet due to human triggered avalanches being very likely in wind exposed terrain. Over the last 24 hours we have seen high winds and at times heavy snowfall, which is creating wind slabs that are widespread. The danger is CONSIDERABLE below 6000 where wind slabs are less widespread but storm slab and loose wet avalanches are likely. In all sheltered terrain, human triggered storm slab avalanches are likely in very steep terrain. 

How to read the advisory


  • Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
Avalanche Problem 1: Wind Slab
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Over the last 48 hours new wind slabs continue to build with wind speeds in the upper 20 to 30 MPH range in the Northern Mountains and higher still along the West Mountain Crest. Winds were generally out of the S/SW but have been variable depending on time during storm and location. Rapid loading was occurring on leeward slopes and the lee side of even small terrain features around the compass.  These slabs are resting on a variety of old snow surfaces: sun and heat crusts, old wind slabs, wind board, light density snow, and in the northerly terrain weaker faceted snow(the persistent weak layers we have been tracking).  Avalanche size and likelihood will vary quite a bit because of these layers and the slabs resting on top of them. Cracking was widespread in wind affected terrain Saturday and Friday, additional snow and increasing wind velocities through the next few days will add to the likelihood of  both natural and human triggered avalanches. These avalanches have the potential to step down into older wind slabs or deeper buried weak layers creating the potential for large avalanches.  Cornices are also growing large and are very sensitive right now, avoid travel on or under cornices as the possibility of cornice collapses will be high today as well. 

Shallow, dense and sensitive wind slab on skin track from Friday afternoon.

Avalanche Problem 2: Storm Slab
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Warm snow over cold snow has been, and still is piling up. Both SNOTEL sites that we typically reference are down currently (Secesh Summit and Brundage Reservoir) However, as of yesterday morning they had picked up over 2 inches of snow water equivelent (SWE) in 48 hours, which is a large load applied in a relatively short amount of time.  Additional snowfall is forecasted to continue throughout the day today with snow totals varying quite a bit according to elevation (3 to 10 inches).  Slopes over about 30 degrees that don't slide on their own will be primed for a human trigger today.  Stick to lower angle terrain and pay attention to slopes above and around you. If released, there is a possibility that they could step down into weak layers buried deeper in the snowpack.  

Shallow slab of dense snow resting above a weaker layer of the older and colder snow below at 7000 ft. near Goose Lake.

Avalanche Problem 3: Loose Wet
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Rain and rain/snow mix has been falling on the lower elevations all weekend, most likely any of these slopes that were going to avalanche naturally already have done so. However, human triggering a loose wet avalanche below 6000 feet today is still likely. These small avalanches don't move fast but can quickly entrain a large amount of material as they spread out and gain momentum on steep slopes.  These avalanches will likely be found near local roads, in river canyons and in areas we don't normally worry about avalanches.

 With an approaching cold front this afternoon, we should slowly see these suspect low elevation slopes start to stabilize.

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

Dug a pit at 7650' on east side of Sargents yesterday in the midst of the storm. 180 to 200 cm of total snow. 60+ cm of fist to 4 finger new snow sitting on 10 cm pencil hard wind slab. Storm snow failed easy on compression test (CT 7 at interface between fist and 4 finger), but lacked cohesiveness and energy. Also, had a CT 14 at interface above pencil hard slab and fist hard snow above it. Once again lacked cohesion and energy. 

That being said, this was as isolated area and much sketchier conditions exist out there.

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 25 deg. F.
Max. temperature in the last 24 hours: 26 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

Some of the sensors on the Granite Mountain weather station seem to be down. PAC forecasters will try to fix as soon as possible.

Over night Brundage picked up 3 inches of new snow at the base area with moderate winds.

Today in the upper elevations we will have snow before 11am, then snow showers after 11am. High near 29. Windy, with a south southwest wind 38 to 43 mph decreasing to 30 to 35 mph in the afternoon. Winds could gust as high as 55 mph. Chance of precipitation is 100%. Total daytime snow accumulation of 3 to 10 inches possible.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Monday Monday Night Tuesday
Weather: Rain and snow showers, becoming all snow after 11am. High near 37. South wind 15 to 18 mph. Chance of precipitation is 90%. Total daytime snow accumulation of less than a half inch possible. A 50 percent chance of snow showers, mainly before 11pm. Cloudy, with a low around 16. South wind 5 to 10 mph becoming light after midnight. New snow accumulation of less than one inch possible. Snow showers likely, mainly after 11am. Cloudy, with a high near 29. Calm wind becoming south southeast around 6 mph in the afternoon. Chance of precipitation is 60%. New snow accumulation of 1 to 2 inches possible.
Temperatures: high 37 deg. F. low 16 deg. F. high 29 deg. F.
Wind direction: south south south southeast
Wind speed: 15-18 5-10 calm-6
Expected snowfall: less than .5 in. less than 1 in. 1-2 in.
Granite Mountain at 7700 feet.
  Monday Monday Night Tuesday
Weather: Snow before 11am, then snow showers after 11am. High near 29. Windy, with a south southwest wind 38 to 43 mph decreasing to 30 to 35 mph in the afternoon. Winds could gust as high as 55 mph. Chance of precipitation is 100%. Total daytime snow accumulation of 3 to 7 inches possible. A 50 percent chance of snow showers. Cloudy, with a low around 14. Wind chill values between -3 and 2. Breezy, with a southwest wind 19 to 24 mph decreasing to 13 to 18 mph after midnight. New snow accumulation of around an inch possible. Snow showers likely, mainly after 11am. Cloudy, with a high near 22. South southwest wind 11 to 15 mph. Chance of precipitation is 60%. New snow accumulation of 1 to 3 inches possible.
Temperatures: high 29 deg. F. low 14 deg. F. high 22 deg. F.
Wind direction: south southwest southwest south southwest
Wind speed: 30-43 gusting 55 13-24 11-15
Expected snowfall: 3-7 in. 1 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.