THIS AVALANCHE ADVISORY EXPIRED ON March 21, 2017 @ 6:13 am
Avalanche Advisory published on March 20, 2017 @ 6:13 am
Issued by Dave Bingaman - Payette Avalanche Center
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The Avalanche Danger is Moderate today at all elevations and aspects.  Human triggered loose, wet avalanches remain possible on all steep slopes.  On leeward(E, NE, N, NW)  facing slopes  in the highest elevations, thin wind slabs may be reactive to the weight of a skier or snowmobile.   Cornice failures are also a major concern,  cornices are large and overhanging ridge lines much farther than you might expect.  Avoid traveling 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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We are starting to sound like a broken record but warm weather and high elevation rain are continuing to degrade our snow pack.  With another 48 hours of above freezing temperatures and the rain/snow line rising to near 8000 feet today, wet slides continue to be our main concern. Temperatures at local Snotel sites are around 36 this morning and the 7600 ft Granite weather station is hovering right at 32.  Local Snotel Sites have lost between 30 and 40 inches of their snow totals in the last 10 days as a result of the wet, warm weather.   With the lack of freezing temperatures, especially below 7,500 feet, you run a good chance of starting a loose wet avalanche in steep terrain.  With a series of crusts buried deep in our snow pack, the potential for deep, wet slab avalanches is lurking in our snow pack as well.  Thursday looks like a potential cool down with low temperatures below freezing in the forecast, but until our snow pack sees a hard freeze, you should avoid steep slopes especially those with terrain traps, gullies or bad consequences if a wet slide were triggered.

Cornices are a serious concern right now as well, if you are up high near ridge lines, yo can see monster cornices on pretty much all of the leeward slopes.  See the recent observations for some more about large cornices.  Avoid travel on or near corniced ridge lines and limit the amount of time you spend on slopes below them as well.

Avalanche Problem 2: Wind Slab
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Winds have been whipping up high for the last few days.  While not a lot of snow has been available for transport recently, a few more inches of upper elevation snow fell yesterday above 7400 feet adding to the problem.  We found shallow wind slabs to be fairly widespread near the highest ridges on Friday and have added a few additional inches of snow with 30 mph wind gusts to create some thicker slabs over the weekend.  Many of these wind slabs are resting on firm snow below whether rain, heat or wind crusts, which makes for an almost ideal sliding or bed surface.  Most of these slabs will found on E, NE, N and NW facing slopes.  

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

No new avalanches have been reported over the weekend but I am guessing that not a lot of folks braved the rain and sloppy snow to get out and recreate so there are probably a few new natural slides that have gone unreported.  Cornices yesterday were the big news, these monsters are under some serious strain right now and are beginning to fail and to creep or glide down the ridges almost to the point of failure in quite a few places.   I checked out what looked like a crevasse field on the ridge at Tamarack Resort yesterday and found a series of offset cracks starting near the edge of a large overhanging cornice going back into the flats an uphill on a small knoll scattered over a 100 to 200 foot area.  These cracks are the result of the strain of the cornices slowly rolling off the edge of the ridge but not yet to point of failure....think calving glaciers.  The crack in the photo below was deep enough that I could not see the bottom and was quite a ways back and uphill of the actual cornice.  Further to the south of the Summit chair lift there is a glide crack that is running about 500 feet along the ridge were the snow is slowly rolling downhill.  Big cornices demand your respect right now and your best bet is to avoid them.

Glide cracks at Tamarack Resort-3/19/17

Large overhangs near Victor Saddle -3/17/17

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 32 deg. F.
Max. temperature in the last 24 hours: 33 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
weather

SHORT TERM...Today through Tuesday...Continued southwest flow aloft will keep showers in the forecast in the short term, along with isolated afternoon/evening thunderstorms. Latest models have slightly decreased QPF through the short term, especially NAM and SREF, and we chose to follow suit. Therefore QPF totals through Tuesday afternoon now average 0.25 to 0.50 inch in the mtns and 0.07 to 0.15 in the valleys. Instability increases, especially Tuesday, and is sufficient to warrant a mention of thunderstorms each afternoon and evening. Rivers will remain high, with some in minor flood stage. See Hydrology section below. Temps will also remain above normal as warm air advection will not end until a short wave trough moves in late Tuesday. This same trough will help increase instability.

LONG TERM...Tuesday night through Sunday...Pacific short wave trough will swing inland Tuesday evening with showers and a slight chance of thunderstorms. NAM in particular has enough instability to continue a slight chance of thunderstorms through the night. General troughing through the remainder of the period will continue a chance of showers each day with snow level 5000-6000 feet MSL. Most significant Pacific cold front currently forecast to come in Friday night with showers and local gusty winds. Breezy and cooler Saturday and Sunday.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Monday Monday Night Tuesday
Weather: Showers, with thunderstorms also possible after noon. High near 48. East southeast wind 5 to 7 mph. Chance of precipitation is 80%. A chance of showers and thunderstorms. Cloudy, with a low around 36. East wind around 7 mph. Chance of precipitation is 40%. Showers likely, then showers and possibly a thunderstorm after noon. High near 48. South wind 6 to 8 mph. Chance of precipitation is 80%
Temperatures: 48 deg. F. 36 deg. F. 48 deg. F.
Wind direction: ESE E S
Wind speed: 5-7 Around 7S 6-8
Expected snowfall: 0 in. 0 in. 0 in.
Granite Mountain at 7700 feet.
  Monday Monday Night Tuesday
Weather: Snow showers. Some thunder is also possible. High near 44. South wind 9 to 13 mph. Chance of precipitation is 90%. Little or no snow accumulation expected. A chance of snow showers before midnight, then a chance of rain and snow showers. Some thunder is also possible. Cloudy, with a low around 33. South wind 11 to 15 mph. Chance of precipitation is 50%. Little or no snow accumulation expected. Rain and snow showers. Some thunder is also possible. High near 41. South wind around 14 mph. Chance of precipitation is 90%. Little or no snow accumulation expected.
Temperatures: 44 deg. F. 33 deg. F. 41 deg. F.
Wind direction: S S S
Wind speed: 9-13 11-15 14
Expected snowfall: 0 in. 0 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.