THIS AVALANCHE ADVISORY EXPIRED ON February 23, 2017 @ 6:54 am
Avalanche Advisory published on February 22, 2017 @ 6:54 am
Issued by George Halcom - Payette Avalanche Center
bottom line

The avalanche danger is CONSIDERABLE above 7,000 feet. Snow and strong winds have created slabs in exposed and sheltered terrain on multiple aspects. Multiple generations of wind slabs may be sensitive to the weight of skiers and riders, may be up to 3’ thick, and have formed on top of a variety of surfaces.  Below 7,000 feet the avalanche 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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Winds out of the West-Southwest, along with warmer snow did a good  job yesterday of producing a heavier, slabby layer on the surface of the snow on multiple aspects where the snow was not protected, giving us an upside down layer that is now buried by 4-6 inches of light density snow as the storm cooled down. The winds were very strong yesterday, knocking mature trees over, and producing natural slab avalanches up to 3 feet deep, as seen in the photo above of an avalanche yesterday on Granite Mountain's Baby Face (NNE 7200ft).

 

 

Avalanche Problem 2: Storm Slab
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 In middle and upper elevations, where the wind did not got a chance to affect the new snow or the snow was too dense (wet), storm slabs will be likely. Be heads up when traveling in/on/above or below steep terrain today. Even a small convex on a slope could cause a storm slab to be triggered. 

 

 

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 15, 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,  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. 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.

We rely on our snowmobiles to bring you quality forecasts. Currently two of our sleds have nearly 8,000 miles on them. We need your help raising funds for replacements! Please contact us if you can help in any way forecast@payetteavalanche.org or click DONATE tab.

recent observations

Yetserday, Brundage Catski reported a natural slab avalanche up to 3 feet deep Granite Mountain's Baby Face (NNE 7200ft).  Check out the observation in our observations section, where othe skiers have reported triggering similar slides.

Monday we got a report of a natural wind slab avalanche on the Brundage ridge line just out of bounds from the ski area on a west aspect at 7,200 feet. We don't know much, however, we do know that it was approx. 200 feet wide with a crown depth of approx. 20 inches.

Sunday we had a report from local guides of natural storm slab avalanches on northwest aspects at around 7,000 feet on 'Double North'. These avalanches were failing on 38 degree slopes and ran 150 feet with a crown of approx. 1 foot. On Slab Butte the guides were able to get slabs to release 10-12 inches deep on steep roll overs with ski cuts on west aspects.

Natural avalanches are the #1 RED FLAG for dangerous avalanche conditions. 

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 27 deg. F.
Max. temperature in the last 24 hours: 30 deg. F.
Average wind direction during the last 24 hours: west-southwest
Average wind speed during the last 24 hours: 8 mph
Maximum wind gust in the last 24 hours: 38 mph
New snowfall in the last 24 hours: NA inches
Total snow depth: NA inches
weather

TODAY Snow showers likely. Cloudy, with a high near 23. West southwest wind 6 to 9 mph becoming north in the afternoon. Chance of precipitation is 70%. Total daytime snow accumulation of 1 to 3 inches possible.

LONG TERM...Thursday night through Tuesday...Weak ridging over the region Thursday night through Saturday as a weak upper level low pressure system moves south along the Pacific Northwest coast. This will bring west-southwesterly flow over the region and limit cold air advection. Limited moisture remains over the area but there could be enough for showers across the higher elevations Friday and Saturday afternoons. Models continue to differ on their handling of another stronger upper level low pressure system forecast to move south along the coast Friday night through Saturday. Confidence remains low as each new model run continues to shift this low pressure system farther south along the California coast before it weakens as it shifts inland Sunday/Monday. At the moment, the best chance for precipitation looks to be Monday with a warm frontal passage. Precipitation type will be tricky, but it would appear the valleys would see a mix of wet snow and rain below 4000 feet with the mountains seeing all snow. Above-freezing ground temperatures will likely limit snowfall as well. A warming trend follows with an upper level ridge building over the west coast through the middle of next week. Moist northwesterly flow could bring showers to the higher terrain Tuesday and Wednesday. Below normal temperatures Friday will slowly increase, reaching near normal by Wednesday.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Wednesday Wednesday Night Thursday
Weather: Snow showers likely, mainly after 11am. Cloudy, with a high near 32. Light and variable wind becoming northwest 5 to 7 mph in the afternoon. Chance of precipitation is 60%. New snow accumulation of less than a half inch possible. A 40 percent chance of snow showers. Mostly cloudy, with a low around 16. North wind around 8 mph. New snow accumulation of less than a half inch possible. A 40 percent chance of snow showers. Mostly cloudy, with a high near 27. North northwest wind 8 to 10 mph. New snow accumulation of less than a half inch possible.
Temperatures: high 32 deg. F. low 16 deg. F. high 27 deg. F.
Wind direction: northwest north north-northwest
Wind speed: 5-7 8 8-10
Expected snowfall: less than one half in. less than one half in. less than one half in.
Granite Mountain at 7700 feet.
  Wednesday Wednesday Night Thursday
Weather: Snow showers likely. Cloudy, with a high near 23. West southwest wind 6 to 9 mph becoming north in the afternoon. Chance of precipitation is 70%. Total daytime snow accumulation of 1 to 3 inches possible. A 40 percent chance of snow showers. Mostly cloudy, with a low around 11. Wind chill values between -4 and 6. North wind 13 to 16 mph. New snow accumulation of less than a half inch possible. A 50 percent chance of snow showers. Cloudy, with a high near 19. Wind chill values between -6 and 4. North wind 13 to 16 mph. New snow accumulation of less than one inch possible..
Temperatures: 23 deg. F. low 11 deg. F. high 19 deg. F.
Wind direction: west-southwest north north
Wind speed: 6-9 13-16 13-16
Expected snowfall: 1-3 in. less than one half in. Less than 1 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.