THIS AVALANCHE ADVISORY EXPIRED ON March 19, 2017 @ 6:07 am
Avalanche Advisory published on March 18, 2017 @ 6:07 am
Issued by Dave Bingaman - Payette Avalanche Center
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The Avalanche Danger is MODERATE  today at all elevations/aspects.  Loose, wet avalanches will be your main concern today,  but upper elevation lee slopes are now sporting a thin and reactive wind slab layer as well as 3-5 inches of sled cooling, ski carving new snow.  Cornice failures are also a major concern,  cornices are very large and overhanging ridgelines much farther than you might expect.  Avoid travelling near the edges of and spending time below these monsters.

How to read the advisory


  • Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Loose Wet
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Warm weather is continuing to degrade our snowpack.  Temperatures at local Snotel sites and at the 7600 ft Granite weather station are above 40 this morning.  Local Snotel Sites have lost between 20 and 30 inches of their snow pack in the last 7 days as a result of the wet, warm weather.  Yesterday started out cold and warmed quickly with firm snow and very warm sleds in the morning followed by warm and slushy conditions in the afternoon.  Temperatures today will begin to drop around noon and cool as a cold front moves into the area keeping upper elevation temperatures right around freezing overnight.  Temperatures are forecasted to remain above freezing through Sunday night even in the mid and upper elevations.  With the lack of freezing temperatures, especially below 7,600 feet, you still run a good chance of starting a loose wet avalanche in steep terrain.  Scattered rain showers and periods of  heavier rain today and tonight will increase the potential for natural and human caused wet slides through the next 48 hours.

Avalanche Problem 2: Cornice
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Many of the ridgelines in the area are still sporting some very large, overhanging cornices.  We had a report of a large, human triggered cornice failure earlier this week and also have seen many areas where large sections of cornice have already succumbed to the pull of gravity.  Cornice failures are very common in the spring and we have a bumper crop of monster cornices this year.  Avoid travel on or near large cornices and stay off slopes that have large, overhanging cornices above them.  Make sure you are aware of where the snow begins and the ridgelines end,  don't venture out past the last trees and rocks that mark the edge. Notice how far the cornices in the photos below are extending beyond the ridges.

      

advisory discussion

Snowmobiler/Snowbiker Travel Restrictions: 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.  It is your responsibility to know where closures exist on the forest.

The Granite Mountain Area Closure is in effect Jan15-March 31, please respect Snowcats operating, signed and unsigned closures and other users 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, North of Boulder Mtn, East of Rapid Peak, North of the 20 mile drainage, 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").  

Ski areas are closed to snowmobile traffic, last week a group of snowmobilers poached the Northern portion of Tamarack Resort crossing under a fixed and signed rope line and left trenches on 3 of the ski runs that don't get groomed. Don't be "that guy" that gives sledders a bad name, please respect boundaries, snowmobiling at a ski resort is a low blow and a safety concern.

 

recent observations

Yesterday we toured near Victor Saddle and through the Trail Creek drainage and found several recent wet slides.  The debris piles were fairly large (D2) and were easily large enough to bury a skier or sledder.  The cornices were impressive with sections 20 feet thick overhanging 30 feet.  We also saw some large piles of debris below some of these monsters where pieces had failed and started small wet slides below.  We were pleasantly surprised to find several inches of new snow above 7500 feet that was a welcome relief for our hot sleds and provided some great spring turns on some of the steeper terrain near the ridgetops.  A thin wind slab layer was also found near the ridgetops.  It was in the 3-6 inch range but was reactive on roll overs and in some of the leeward terrain.  With a little bit of new snow available for transport and winds continuing to gust to near 30 today, I would watch for growing wind slabs that are resting on a variety of firm surfaces below.  The photos below are examples of the wet slides that are happening as temperatures climb throughout the day.  They are from upper and middle elevation slopes that slid naturally or with the help of a falling cornice chunk in the last day or two,

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 41 deg. F.
Max. temperature in the last 24 hours: 42 deg. F.
Average wind direction during the last 24 hours: WSW
Average wind speed during the last 24 hours: 8 mph
Maximum wind gust in the last 24 hours: 24 mph
New snowfall in the last 24 hours: NA inches
Total snow depth: NA inches
Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Saturday Saturday Night Sunday
Weather: Showers. High near 45. South wind 6 to 11 mph. Chance of precipitation is 100%. Showers. Low around 33. South wind 5 to 9 mph becoming west after midnight. Chance of precipitation is 100% Showers likely, mainly before noon. Mostly cloudy, with a high near 44. Calm wind becoming southwest around 5 mph in the afternoon. Chance of precipitation is 60%.
Temperatures: 45 deg. F. 33 deg. F. 44 deg. F.
Wind direction: S S SW
Wind speed: 6-11 5-9 Around 5
Expected snowfall: 0 in. 0 in. 0 in.
Granite Mountain at 7700 feet.
  Saturday Saturday Night Sunday
Weather: Rain showers before noon, then rain and snow showers. Temperature falling to around 32 by 3pm. Breezy, with a south wind 17 to 23 mph, with gusts as high as 33 mph. Chance of precipitation is 100%. Little or no snow accumulation expected. Rain and snow showers, becoming all snow after midnight. Low around 26. Breezy, with a south southwest wind 16 to 21 mph becoming west 8 to 13 mph after midnight. Winds could gust as high as 31 mph. Chance of precipitation is 100%. New snow accumulation of less than a half inch possible. Snow showers likely. Mostly cloudy, with a high near 36. South southwest wind 7 to 9 mph. Chance of precipitation is 60%. New snow accumulation of less than one inch possible.
Temperatures: Falling to 32 by noon deg. F. 26 deg. F. 36 deg. F.
Wind direction: S SSW SSW
Wind speed: 17-23, gusts tp 33 16-21, gusts to 31 7-9
Expected snowfall: 0 in. Trace 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.