THIS AVALANCHE ADVISORY EXPIRED ON March 2, 2017 @ 6:18 am
Avalanche Advisory published on March 1, 2017 @ 6:18 am
Issued by George Halcom - Payette Avalanche Center
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The avalanche danger is CONSIDERABLE above 7,000 feet where human triggered avalanches are likely. New snow combined with variable winds have formed a new batch of wind slabs on all leeward terrain in the upper elevations. In the middle elevations, on steep slopes that were not affected by the wind, loose dry avalanches are the primary problem and the danger is MODERATE. Below 6,000 feet where less new snow has fallen the danger is LOW.

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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Variable winds along with a couple inches of fresh snow last night, and over the last few days have loaded slopes and cross loaded terrain features on all aspects above 7,000 feet. Winds at the Granite Mountain weather station have been out of the west, southwest, northwest, and even south-southeast. The winds have been light to moderate in speed, which is perfect to move the low density powder around with out causing the light snow to go air borne and sublimate. Today expect to find a wide range of wind slab depth and sensitivity from shallow and sensitive, to thick and stubborn. One thing that all the wind slabs will have in common is that they will be located on leeward aspects in exposed terrain above 7,000 feet. Be on the look out for any slopes that look pillowy, rippled, or fat with new snow. 

Also, keep in mind that this new round of snow is going to do a great job of camouflaging the older and stiffer wind slabs that still exist on most upper elevation terrain on the north half of the compass. If an avalanche was triggered today on the north half of the compass, it could step down into older wind slabs causing a much larger avalanche.

 

Avalanche Problem 2: Loose Dry
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Cold temperatrues and low density snow will keep loose dry avalanches on our radar today. In steep terrain, be aware that these normally benign 'sluffs' can entrain a fair amount of snow and be dangerous if you are caught and taken into a terrain trap or over cliffs or rocks. Fortunately this problem is easy to predict and avoid. If travelling in steep terrain ( slopes over 35 degrees) use slope cuts to help mitigate the loose snow and keep the sluff below you as you travel down slope.

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 responsiblity to know where closures exist on the forest.

The Granite Mountain Area Closure is in effect Jan15-March 31, 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, 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").

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.We have equipment that is overdue for replacement but lack the funds to purchase new gear including weather station parts and our forecast sleds.  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

Local guides reported triggering small soft storm slabs 4-6 inches deep on West, and South aspects of Slab Butte yesterday. 

Great skiing and riding conditions exist out there right now. Stay safe and enjoy the deep blower powder!

If you see or trigger any avalanches while you are out, please let us know at payetteavalanche.org or use the OBSERVATION tab at the top of the website. 

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 13 deg. F.
Max. temperature in the last 24 hours: 14 deg. F.
Average wind direction during the last 24 hours: west-northwest
Average wind speed during the last 24 hours: 6 mph
Maximum wind gust in the last 24 hours: 15 mph
New snowfall in the last 24 hours: NA inches
Total snow depth: NA inches
weather

Today, there is a 50 percent chance of snow showers. Cloudy, with a high near 21. Wind chill values between -4 and 6. Southwest wind 15 to 17 mph. Total daytime snow accumulation of 1 to 2 inches possible.

LONG TERM...

Thursday night through Tuesday...Moisture flowing
inland ahead of an upper level trough will spread scattered showers
into Baker County Oregon and the west central Idaho mountains
Thursday night and Friday morning. Precipitation will reach the
Boise Mountains and lower Treasure Valley Friday afternoon, then
spread south across the remainder of our area Friday night, becoming
widespread over the higher terrain of central Idaho and Baker County
Oregon. Snow levels will be near 5000 feet, then lower to around
4000 feet by Sunday morning as the trough moves inland. Snow showers
will continue over the higher terrain Sunday night and Monday, with
a mix of rain and snow in the valleys. Snow could briefly accumulate
in the lower valleys late Sunday night and Monday morning, but will
melt by afternoon as temperatures rise into the 40s. Scattered
showers will continue Monday night and Tuesday, with gradual warming
as the upper level flow shifts into the west and southwest.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Wednesday Wednesday Night Thursday
Weather: A 50 percent chance of snow showers. Cloudy, with a high near 30. South southwest wind 8 to 10 mph. New snow accumulation of less than a half inch possible. A 20 percent chance of snow showers. Cloudy, with a low around 19. South wind 5 to 9 mph. Cloudy, with a high near 34. South wind 6 to 9 mph.
Temperatures: high 30 deg. F. low 19 deg. F. high 34 deg. F.
Wind direction: south-southwest south south
Wind speed: 8-10 5-9 6-9
Expected snowfall: less than one half in. 0 in. 0 in.
Granite Mountain at 7700 feet.
  Wednesday Wednesday Night Thursday
Weather: A 50 percent chance of snow showers. Cloudy, with a high near 21. Wind chill values between -4 and 6. Southwest wind 15 to 17 mph. New snow accumulation of 1 to 2 inches possible. A 20 percent chance of snow showers. Cloudy, with a low around 17. Southwest wind 11 to 14 mph. Cloudy, with a high near 26. South southwest wind 14 to 18 mph.
Temperatures: high 21 deg. F. low 17 deg. F. high 26 deg. F.
Wind direction: southwest southwest southwest
Wind speed: 15-17 11-14 14-18
Expected snowfall: 1-2 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.