THIS AVALANCHE ADVISORY EXPIRED ON February 28, 2017 @ 6:18 am
Avalanche Advisory published on February 27, 2017 @ 6:18 am
Issued by Kent May - Payette Avalanche Center
bottom line

The avalanche danger is CONSIDERABLE above 6,000 feet due to human triggered avalanches being likely. New snow combined with winds out of the south, west, and southwest have caused a new batch of wind slabs on all leeward terrain. On steep slopes that were not affected by the wind, loose dry avalanches are the primary problem. Below 6,000 feet where new light powder rests on a slick crust the danger is MODERATE.

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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Yesterday, as the storm moved through, we had light to moderate winds that did a great job moving the low density powder around in exposed terrain in upper elevations. 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.

Today is going to be a great day for low angle slopes in the middle and lower elevations.

Avalanche Problem 2: Loose Dry
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Loose dry avalanches can be found on all steep aspects that were not affected by the wind yesterday. The low density powder that has fallen, and will continue to fall, is resting on a firm crust below 7,000 feet making the loose dry avalanche problem even worse. The combination of light snow, resting on a stout crust, is making for poor bonding between the new and the old snow. This poor bond is a great recipe for loose dry avalanches in steep terrain.

Fortunately this is an avalanche problem that is easy to predict and easy to avoid. Stick to lower angle slopes today and avoid committing to slopes above terrain traps.

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

Whoa Nelly! Yesterday was the surprise powder day of the year! The forecasts for Sunday were calling for 3-5 inches, that was easily doubled in most locations around the advisory area. Tamarack is reporting 11 inches of new over the last 24 hours and Brundage has picked up 10 inches. The most impressive totals yesterday were at middle elevations where it was not too cold, nor too windy. 

Yesterday above tree line we found wind slabs building on east, northeast, and north terrain. The sensitivity of these wind slabs had a direct correlation to how deep the snow had been deposited. I found a wide range of wind slabs from sensitive and thin, to thick and stubborn. 

Below tree line, on steep terrain, you could easily get the new snow to move and loose dry avalanches were easily triggered on safe test slopes with ski cuts. 

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 11 deg. F.
Max. temperature in the last 24 hours: 14 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 7 mph
Maximum wind gust in the last 24 hours: 21 mph
New snowfall in the last 24 hours: 6 inches
Total snow depth: NA inches
weather

Today snow showers. Temperature falling to around 10 by 5pm. Wind chill values between -4 and 6. Southwest wind 5 to 7 mph becoming calm. Chance of precipitation is 100%. Total daytime snow accumulation of 1 to 3 inches possible.

Tonight snow showers. Low around 10. Wind chill values between -6 and 3. Breezy, with a south southwest wind 11 to 21 mph. Chance of precipitation is 100%. New snow accumulation of 3 to 5 inches possible.

LONG TERM...Tuesday night through Sunday...Westerly flow aloft will continue to bring moisture inland across the Pacific Northwest states. Precipitation will be mainly over northern areas, including Baker County Oregon and the central Idaho mountains, through Thursday night. Showers are expected to spread as far south as northern Nevada Friday through the weekend as a weak upper level trough crosses the area, with snow levels near 5000 feet. Temperatures will gradually warm to near normal by Friday. Models are in good agreement, and run to run consistency is above average. &&

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Monday Monday Night Tuesday
Weather: Snow showers. High near 26. South southwest wind 3 to 7 mph. Chance of precipitation is 100%. Total daytime snow accumulation of 1 to 2 inches possible. Snow showers. Low around 16. South southeast wind 5 to 9 mph. Chance of precipitation is 100%. New snow accumulation of 1 to 2 inches possible. Snow showers, mainly before 11am. High near 26. South wind 7 to 10 mph becoming west in the afternoon. Chance of precipitation is 90%. New snow accumulation of around an inch possible.
Temperatures: high 26 deg. F. low 16 deg. F. high 26 deg. F.
Wind direction: south-southwest south-southeast south
Wind speed: 3-7 5-9 7-10
Expected snowfall: 1-2 in. 1-2 in. 1 in.
Granite Mountain at 7700 feet.
  Monday Monday Night Tuesday
Weather: Snow showers. Temperature falling to around 10 by 5pm. Wind chill values between -4 and 6. Southwest wind 5 to 7 mph becoming calm. Chance of precipitation is 100%. Total daytime snow accumulation of 1 to 3 inches possible. Snow showers. Low around 10. Wind chill values between -6 and 3. Breezy, with a south southwest wind 11 to 21 mph. Chance of precipitation is 100%. New snow accumulation of 3 to 5 inches possible. Snow showers. High near 19. Wind chill values between -1 and 6. West wind 11 to 14 mph. Chance of precipitation is 90%. New snow accumulation of 2 to 4 inches possible.
Temperatures: falling to 10 deg. F. low 10 deg. F. high 19 deg. F.
Wind direction: southwest south-southwest west
Wind speed: 5-7 11-21 11-14
Expected snowfall: 1-3 in. 3-5 in. 2-4 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.