THIS AVALANCHE ADVISORY EXPIRED ON December 13, 2018 @ 8:36 am
Avalanche Advisory published on December 12, 2018 @ 8:36 am
Issued by George Halcom - Payette Avalanche Center
Avalanche Problem 1: Normal Caution
  • Character ?
  • Aspect/Elevation ?

Greetings! The Payette Avalanche Center is open for the year, and will begin posting advisories 4-5 days a week starting this Saturday December 15th. Early season cautious conditions are the name of the game right now. Skiers are traveling gingerly, and snowmobiling off trail is probably going to cost some folks a good bit of money for repairs as much more snow is needed to cover up all the rocks and logs in our advisory area. Keep praying for snow it is working.

At lower elevations, the snow pack is very thin. As you travel up in elevation, there is enough snow to be concerned with avalanche potential. Smooth planar slopes are few and far between, but should be approached with caution, especially those slopes that are above 30 degrees. The snow pack is already complex, and is harboring weak layers like basal facets, surface hoar, near surface facets, and denser, upside-down mid layers. Check out some of the observations on the observations page like this snowsuit from a level 1 AIARE avalanche course last weekend from Payette Powder Guides.

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 16 deg. F.
Max. temperature in the last 24 hours: 18 deg. F.
Average wind direction during the last 24 hours: W
Average wind speed during the last 24 hours: 15 mph
Maximum wind gust in the last 24 hours: 24 mph
New snowfall in the last 24 hours: 7 inches
Total snow depth: 65 inches


Area Forecast Discussion
National Weather Service Boise ID
309 AM MST Wed Dec 12 2018

.SHORT TERM...Today through Thursday...Rain and snow will taper
off this morning from west to east as the upper trough passes into
eastern Idaho. Northwest flow and instability will favor
scattered showers in the east-central Oregon and west-central
Idaho mountains through the afternoon, while lower valleys are
dry. Expect afternoon snow showers to bring little additional
accumulation to what falls through late morning. Easterly winds
early this morning will shift to the northwest by afternoon with
gusty surface winds supported by strong winds aloft. An upper
ridge is quick to build over the area tonight and Thursday. An
accompanying warm frontal passage could bring a snow shower to
northern Baker and Adams counties Thursday morning, but otherwise
the area remains dry. Temperatures will be near normal through

.LONG TERM...Thursday night through Tuesday...The progressive
pattern will continue the unsettled weather. Following a break
Thursday night and Friday, a fast moving Pacific weather system
will spread snow showers across most of our area Friday night,
mainly over the central Idaho mountains. Dry weather is expected
on Saturday under weak high pressure. An upper level trough will
bring mountain snow and valley rain showers Sunday through Monday,
with the best chance Sunday night. Model solutions for the
northwest U.S. diverge starting Monday night, with increasing
uncertainty how far south precipitation will reach Monday night
through Wednesday. Confidence is above average that high pressure
will build over California during that period, but models differ
on how far north its influence will extend. Temperatures will be
around 5 degrees above normal through the period.


.AVIATION...Expect mountain obscuration and areas of MVFR/local
IFR conditions in snow and rain through 12z. After 12z
precipitation will end at lower elevations and conditions will
improve from the west, with mainly VFR. Scattered snow showers
will continue over the Idaho mountains through this afternoon.
Surface winds will be west 10-20 kts, except 15-30 kts south and
east of KMUO. Winds aloft near 10k feet MSL will be northwest
30-40 kts.


ID...Winter Weather Advisory until 11 AM MST this morning
OR...Winter Weather Advisory until 10 AM PST this morning ORZ062.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Wednesday Wednesday Night Thursday
Weather: Snow showers, mainly before noon. High near 30. West wind 7 to 9 mph. Chance of precipitation is 80%. Total daytime snow accumulation of less than one inch possible. Mostly cloudy, with a low around 13. Calm wind. Mostly cloudy, with a high near 29. Calm wind becoming south around 6 mph in the afternoon.
Temperatures: 30 deg. F. 13 deg. F. 29 deg. F.
Wind direction: West Calm South
Wind speed: 7-9 MPH 0 MPH 6 MPH
Expected snowfall: Less than one in. 0 in. in.
Granite Mountain at 7700 feet.
  Wednesday Wednesday Night Thursday
Weather: Snow showers, mainly before 11am. High near 19. Wind chill values between -2 and 5. Blustery, with a west northwest wind 11 to 21 mph, with gusts as high as 30 mph. Chance of precipitation is 90%. Total daytime snow accumulation of 1 to 2 inches possible. Mostly cloudy, with a low around 12. South southwest wind 5 to 9 mph. A 20 percent chance of snow before 11am. Partly sunny, with a high near 24. South wind 9 to 11 mph.
Temperatures: 19 deg. F. 12 deg. F. 24 deg. F.
Wind direction: West Northwest South Southwest South
Wind speed: 30 MPH 5-9 MPH 9-11 MPH
Expected snowfall: 1-2 in. 0 in. 0 in.

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.