THIS AVALANCHE ADVISORY EXPIRED ON February 5, 2017 @ 6:12 am
Avalanche Advisory published on February 4, 2017 @ 6:12 am
Issued by Dave Bingaman - Payette Avalanche Center
bottom line

The Avalanche Danger is HIGH on all aspects at all elevations.  High winds, heavy snowfall, rain and the potential for rain above 6000 feet combined with above freezing temperatures are creating dangerous avalanche conditions throughout the area.  Lower elevation avalanches will be likely on steep slopes below 5000 feet.  Above 7000 feet wind and storm slabs have been building over the last 24 hours.  Today is a good day to avoid being on or under terrain steeper than 30 degrees.

How to read the advisory


  • Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
Avalanche Problem 1: Wind Slab
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Yesterday new wind slabs built rapidly throughout the day.  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). Cracking was widespread in wind affected terrain as these features were forming yesterday and additional snow and wind last night and 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 a large avalanche.  Rapid cornice formation was also occurring on ridgetops avoid travel on or under cornices as the possibility of cornice collapses will be high today as well.  Use good travel practices, avoid steeper slopes today and keep your eyes on your partners. Stick to low angle meadows and basins if you are snowmobiling and head to the resort if you are skiing, today is not the day to roll the dice on steep terrain. 

 

Avalanche Problem 2: Storm Slab
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Warm snow over cold snow is piling up right now.  Some upper elevations have already passed the 12 inch mark.  Heavy snowfall is forecasted to continue throughout the day today and will add depth and weight and likely overload the strength of the cold snow below.  Slopes over about 30 degress 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. A Winter Storm Warning and Avalanche Warning are in effect through tomorrow afternoon with the potential for upwards of 20 inches of new snow in the upper elevations.

Avalanche Problem 3: Loose Wet
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Rain is possible at elevations above 6000 feet today and tomorrow. Rain on snow can quickly produce natural loose snow avalanches in steep terrain especially in the lower elevations that have a significant snowpack right now.  These avalanches will likely be found near local roads, in river canyons and in areas we don't normally worry about avalanches.

advisory discussion

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.

Snowmobiler/Snowbiker Travel Restrictions:  a quick reminder that the Granite Mountain Area Closure is now in effect.  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. 

FOUND on Goose Lake Road Wednesday near Brundage Reservoir- prescription glasses in case.  Email us at forecast@payetteavalanche.org if these look familiar.

recent observations

Yesterday was just the beginning of a multi day wind and snow event that has elevated the avalanche danger.  We watched wind slabs growing and rapid loading occurring on almost all the terrain we traveled through on Granite Mountain.  In addition the snow surface got progressively more cakey and thick in wind affected terrain(see ski photo below). Cracking and ski induced failures of small wind slabs on our tour were widespread.  The wind was gusting into the 30 mph range and easily transporting the new snow.  We found several persistent grain types in the snowpack on different aspects as well. While it is unlikely, this storm could be the formula to unleash some of our persistent weak layer problems.

Powder turns on skis and sleds were deep in protected terrain and we found great riding conditions in the lower angle terrain.  If you are using the Goose Lake Road be aware that there are some inconsistencies in the groomed trail and reduce your speed to allow for some surprising features.  We aren't sure what the problem is but the Valley Country groomer and the Brundage Snowcats are working on smoothing the trail out.

The cornices were also growing rapidly through the day as you can see in the photos below.

          

 

 

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 24 deg. F.
Max. temperature in the last 24 hours: 26 deg. F.
Average wind direction during the last 24 hours: South
Average wind speed during the last 24 hours: 8-12 mph
Maximum wind gust in the last 24 hours: 33 mph
New snowfall in the last 24 hours: NA inches
Total snow depth: NA inches
weather

Today through Monday...Snow across the area is generally confined to the mountainous areas, with rainfall noted elsewhere. A weak transitory ridge has helped to warm temperatures this morning with values in the upper 30s to low 40s across the valleys. Models in decent agreement with periods of shower activity through the day, especially as the ridge continues to breakdown to allow additional, moist southwest flow across the forecast area. Moisture becomes more limited Sunday morning, with the southwestern half of the forecast area looking to see a reprieve from shower activity. A few showers will be possible, but any shower activity of notable coverage is anticipated to fall over Idaho`s central mountains. The area of low pressure which got fairly hung-up west of Vancouver Island breaks free and begins to dive south along the Pacific coastline. As this system advances, another significant push of moisture moves over the majority of the Pacific coastline, and moves inland through the morning. This moisture will approach eastern Oregon by early Monday morning, but dissipates some as it moves into the forecast area. Regardless, shower activity is anticipated, with another decent slug of snowfall possible over the Boise Mountains and Camas Prairie through Monday afternoon.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Saturday Saturday Night Sunday
Weather: Rain and snow Rain and snow Rain and snow
Temperatures: 35 deg. F. 30 deg. F. 36 deg. F.
Wind direction: S S/SW S
Wind speed: 10-15 11-13 11-13
Expected snowfall: 1 in. 1-2 in. 1-2 in.
Granite Mountain at 7700 feet.
  Saturday Saturday Night Sunday
Weather: Snow Snow Snow
Temperatures: 30 deg. F. 23 deg. F. 30 deg. F.
Wind direction: SW SW S/SW
Wind speed: 25 to 28 mph, with gusts as high as 37 24 to 28 mph, with gusts as high as 38 25 to 32 mph, with gusts as high as 43
Expected snowfall: 3-7 in. 5-9 in. 3-7 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.