THIS AVALANCHE ADVISORY EXPIRED ON March 5, 2017 @ 7:03 am
Avalanche Advisory published on March 4, 2017 @ 7:03 am
Issued by Dave Bingaman - Payette Avalanche Center
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The Avalanche Danger is Considerable today above 6000 feet where a combination of high winds and heavy snowfall have created new wind and storm slabs that have fallen on a variety of old snow surfaces.  Below 6000 feet the Danger is Moderate due to less snowfall overnight and warmer temperatures.  With warm temperatures and rising snowlines today, the possibility of loose, wet avalanches will increase in the lower elevations throughout the day.

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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Moderate to high winds gusting into the 30+ range yesterday and last night have created a variety of wind slabs and scouring across the West Central Mountains.  Most of the winds have been coming out of the S and Sw so the greatest wind loading has occurred on Northerly slopes.  Cornices have continued to grow as well and should be avoided like the plague right now.  Yesterday we observed rapid loading and crossloading near the ridgetops as well as mid slope in exposed terrain.  Shallow wind slabs, very stiff wind board or crust and drifts were forming on all exposed terrain.  7-10 inches of snow ushered in this storm system overnight with an additional 6-10 inches expected today.  With continued moderate to high S and SW winds forecasted through the next 36 hours, you are going to find wind slabs of various thickness and sensitivity scattered across the upper elevation terrain.  Avoid steep, wind loaded terrain today and be aware of what is above you, the possibility of natural avalanches will increase through the day today.

Avalanche Problem 2: Storm Slab
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Upper elevation locations have already picked up 7-10 inches of new snow overnight and the snowfall is forecasted to double by this evening.  The new snow has fallen on a variety of old snow surfaces including surface hoar, old wind slabs, heat and wind crusts.  Expect natural and human triggerable avalanches on steep terrain today.  Avoid steep, committing terrain, know your surroundings and watch your partners.  Please take the time to report any avalanche activity that you see or trigger through this storm cycle.  You can send us an email at: forecast@payetteavalanche.org or better yet take 5 minutes and submit your observations through our website. Photos, aspect, elevation, trigger type and depth will help us get the word out and may save a life.

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, 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").

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.

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 24 deg. F.
Max. temperature in the last 24 hours: 28 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: 28 mph
New snowfall in the last 24 hours: NA inches
Total snow depth: 57 inches
weather

SHORT TERM...Today through Sunday...Radar showing plenty of shower
activity moving through western Idaho this morning, with activity
continuing to spread into the west-central mountains of Idaho. Areas
around McCall have been seeing light snow for the last few hours.
Slightly warmer temperatures across the valleys today will keep snow
levels between 4000 and 6000 ft, resulting in rain through this
afternoon. Snow levels will decrease through the evening and
overnight hours as a cold front approaches eastern Oregon. Baker
county of Oregon is expected to rain showers convert to snow this
evening, with additional locations also seeing this conversion with
cooling temperatures. Periods of a rain-snow mix may be possible for
many Treasure and Magic Valley locations due to their snow levels
decreasing to around 2500 ft. The cold front will continue to
progress eastward on Sunday, with models hinting at an increasingly
unstable atmosphere through the afternoon. This may result in a
lightning strike or two Sunday afternoon, or at least the presence of
some showers with graupel through the afternoon. Regarding any
winter related highlights...while snowfall does look decent across
the area, will pass the decision on to the next shift to permit one
additional model glance since they have been lowering snowfall over
the last couple days. Highlights may be desirable with this pattern
with 6 to 12 inches possible over the mountain locations.

.LONG TERM...Sunday night through Friday...Snow levels remain at
valley floors through the first few days of the extended with the
passage of the cold boundary on Sunday. By Sunday night a lot of the
precipitation begins to push eastward, but a secondary wave behind
the cold boundary begins to push its way into the CWA increasing
chances of snow showers once again by Monday afternoon. By Tuesday
another Pacific System begins to make its way into the CWA with the
passage of the warm boundary on Tuesday. Snow levels climb rapidly
back above 5000 feet MSl. After Wednesday models are still
struggling to come in line. They continue to show ridging through
Thursday evening, then the GFS wants to bring another boundary
through the area. The ECMWF is not as fast nor as excited about this
system. Confidence after Wednesday remains low at this time.
Temperatures begin below normal then sit right around or above
normal until Friday. On Saturday there is quite a spread in
temperatures among the models with some showing temperatures in the
mid-upper 50`s for valley locations while others are in the 40`s.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Saturday Saturday Night Sunday
Weather: Rain and snow showers, becoming all snow after 11am. High near 38. South wind 9 to 13 mph. Chance of precipitation is 90%. Total daytime snow accumulation of 1 to 2 inches possible. Rain and snow showers, becoming all snow after 11pm. Low around 26. South southwest wind around 15 mph. Chance of precipitation is 90%. New snow accumulation of 1 to 2 inches possible. Snow showers likely. Cloudy, with a high near 31. South wind 9 to 11 mph. Chance of precipitation is 60%. New snow accumulation of 1 to 2 inches possible.
Temperatures: 38 deg. F. 26 deg. F. 31 deg. F.
Wind direction: S S/SW S
Wind speed: 9-13 15 9-11
Expected snowfall: 1-2 in. 1-2 in. 1-2 in.
Granite Mountain at 7700 feet.
  Saturday Saturday Night Sunday
Weather: Snow showers. High near 27. Breezy, with a south southwest wind 22 to 28 mph, with gusts as high as 38 mph. Chance of precipitation is 90%. Total daytime snow accumulation of 6 to 10 inches possible. Snow showers. Low around 16. Windy, with a south southwest wind 29 to 31 mph, with gusts as high as 41 mph. Chance of precipitation is 90%. New snow accumulation of 3 to 7 inches possible. Snow showers likely. Cloudy, with a high near 20. Wind chill values between zero and 5. Breezy, with a south wind 20 to 22 mph. Chance of precipitation is 70%. New snow accumulation of 1 to 3 inches possible.
Temperatures: 27 deg. F. 16 deg. F. 20 deg. F.
Wind direction: SSW SSW S
Wind speed: 22-28, gusting to 38 29-3, gusting to 41 20-22
Expected snowfall: 6-10 in. 3-7 in. 1-3 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.