THIS AVALANCHE ADVISORY EXPIRED ON March 6, 2017 @ 6:49 am
Avalanche Advisory published on March 5, 2017 @ 6:49 am
Issued by George Halcom - Payette Avalanche Center
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The Avalanche Danger is Considerable today above 6000 feet where a combination of high winds and up to 2 feet of new snow have created new wind and storm slabs that have fallen on a variety of old snow surfaces, and may have a poor bond.  Below 6000 feet the Danger is Moderate due to less snowfall and warmer temperatures. 

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, SW, and last night out of the West at the Granite weather station, so the greatest wind loading has occurred on Northerly slopes, but East is our latest suspect for slab formation. Winds tend to swirl due to terrain influences, and may load and crossload all aspects? Cornices have continued to grow as well and should be avoided like the plague right now.  Friday 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.  Avoid steep, wind loaded terrain today and be aware of what is above you.

Avalanche Problem 2: Storm Slab
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Our mountains have picked up almost 2 feet of new snow in the last 48 hours. 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: 19 deg. F.
Max. temperature in the last 24 hours: 26 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 10 mph
Maximum wind gust in the last 24 hours: 35 mph
New snowfall in the last 24 hours: 12 inches
Total snow depth: 60 inches
weather

SHORT TERM...Today through Monday...Radar demonstrating good
coverage for shower activity this morning, with the front
steadily progressing southeast through the forecast area. The
front will continue its movement, with significant moisture noted
in its wake. Models continue to show impressive moisture across
southwestern Idaho through the afternoon, with significant
snowfall expected for the Owyhee Mountains and the southwest
highlands. Models tapered back on snowfall slightly with this
most recent model run, but changes were not significant enough to
make any alterations to the ongoing Winter Weather Advisory, which
will continue through the afternoon. Snow levels area still
anticipated to widely drop to valley floors through the afternoon,
with a rain-snow mix noted across many valley locations. Truly
the main change made to the forecast for today was to include the
mention of thunder across Baker county in Oregon, along with the
west-central mountains and Weiser area in Idaho. Coverage will be
limited, but models increased instability parameters again when
compared to Saturday. Since lightning was observed in a few
locations, we opted to include it in the current forecast.
Otherwise, the trough producing the precipitation will continue to
advance eastward through Monday, with its axis generally moving
into eastern Idaho by early Monday morning. This will bring a
brief period of a drier, zonal flow tonight. Another push of
Pacific moisture is expected to reach into eastern Oregon late
Monday morning, and cover much of southwestern Idaho by the
afternoon hours. Cooler temperatures will leave much of this
activity as snow as snow levels will fall to valley floors. Models
again indicate some instability during the afternoon, especially
over central Idaho. Indices are not as strong as what is expected
today, so no mention of thunder is included yet.

LONG TERM...Monday night through Saturday...Northwest flow aloft on
Tuesday morning gives way to a more zonal westerly flow by Tuesday
night. Snow levels begin at the valley floors, but slowly start to
climb back up above 5000 feet MSL by Tuesday night. This zonal
westerly pattern brings disturbance after disturbance through the
flow, but most of the precipitation remains in the northern zones of
our CWA, especially the West Central and Boise Mountains. Models
continue to struggle with the day six and seven forecasts so
confidence remains low on precipitation and temperature forecasts
for those days. Temperatures begin Tuesday below normal, but then
climb a few degrees above until Saturday where some models
hint at another chance of going below once again.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Sunday Sunday Night Monday
Weather: Snow showers likely. Some thunder is also possible. Cloudy, with a high near 32. Southwest wind around 10 mph. Chance of precipitation is 60%. New snow accumulation of 1 to 2 inches possible. A 30 percent chance of snow showers. Mostly cloudy, with a low around 19. South wind 7 to 9 mph. New snow accumulation of around an inch possible. Snow showers likely. Cloudy, with a high near 27. South wind 9 to 11 mph. Chance of precipitation is 70%. New snow accumulation of 1 to 3 inches possible.
Temperatures: 32 deg. F. 19 deg. F. 27 deg. F.
Wind direction: Southwest South South
Wind speed: 10 7-9 9-11
Expected snowfall: 1-2 in. 1 in. 1-3 in.
Granite Mountain at 7700 feet.
  Sunday Sunday Night Monday
Weather: Snow showers likely. Some thunder is also possible. Cloudy, with a high near 21. Breezy, with a southwest wind 13 to 22 mph. Chance of precipitation is 70%. New snow accumulation of 2 to 4 inches possible. A 40 percent chance of snow showers. Mostly cloudy, with a low around 13. Wind chill values between -3 and 3. Southwest wind around 15 mph. New snow accumulation of 1 to 2 inches possible. Snow showers likely. Cloudy, with a high near 18. Wind chill values between -3 and 3. South southwest wind 15 to 18 mph. Chance of precipitation is 70%. New snow accumulation of 2 to 4 inches possible.
Temperatures: 21 deg. F. 13 deg. F. 18 deg. F.
Wind direction: Southwest Southwest South-southwest
Wind speed: 13-22 15 15-18
Expected snowfall: 2-4 in. 1-2 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.