Avalanche Advisory published on March 23, 2017 @ 6:30 am
Issued by George Halcom - Payette Avalanche Center
bottom line

The Avalanche Danger will rise to Moderate today as the Sun heats up the snow surface.  Human triggered loose, wet avalanches remain possible on all steep solar slopes. On Southern and Northern slopes in the highest elevations, you may encounter shallow wind slabs that may be reactive to the weight of a skier or snowmobile. 

How to read the advisory

  • Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Loose Wet
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Very Likely
  • Size ?
    Very Large

Last night the mountains got a solid freeze, with some help from the North winds. The Sun is forecasted to come out in force today, which will put smiles on many peoples faces, except the snow pack, which will likely shed snow in the form of loose-wet avalanches. Be cautious throughout the day as the hazard climbs with the temperature, especially on lower elevation SE, S,SW, and W slopes where the sun heats up the snow surface. If you are seeing natural point releases/ loose snow avalanches, and or roller balls, move to an aspect that is cooler, and not in the direct sunlight.




Avalanche Problem 2: Wind Slab
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Very Likely
  • Size ?
    Very Large

With a few inches of new snow in the mountains yesterday, and decent gusts from the Southern end of the compass yesterday, and from the Northern end of the compass last night, you may find some shallow 2-6 inch fresh wind slabs on all aspects in the upper elevations, especially above tree line, that could be sensitive to the weight of  a snowmobile or skier. 




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 responsibility 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").  

Ski areas are closed to snowmobile traffic, last week a group of snowmobilers poached the Northern portion of Tamarack Resort crossing under a fixed and signed rope line and left trenches on 3 of the ski runs that don't get groomed. Don't be "that guy" that gives sledders a bad name, please respect boundaries, snowmobiling at a ski resort is a low blow and a safety concern.

recent observations

Yesterday, we toured the Pearl-Burnside area and witnessed the effects of the last rain event. Most of the giant cornices hung on through the rain, but some did not, and large chunks broke off on many Northern aspects along with numerous debris piles from wet-loose point releases. Runnels in the snow surface were almost completely covered up in the upper elevations by the new snow and wind which gave way to some decent riding conditions. The cool down had frozen the upper few inches before covering it up with a fresh 2-5 inch layer of powder. Below the crust the snow is still saturated and soggy.

Above: Loose snow slides above Burnside Lake

Above: Large cornice break on North aspect into the Box drainage...hard to see

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 20 deg. F.
Max. temperature in the last 24 hours: 33 deg. F.
Average wind direction during the last 24 hours: N
Average wind speed during the last 24 hours: 10 mph
Maximum wind gust in the last 24 hours: 25 mph
New snowfall in the last 24 hours: NA inches
Total snow depth: NA inches

Area Forecast Discussion
National Weather Service Boise ID
327 AM MDT Thu Mar 23 2017

.SHORT TERM...Pacific frontal system along 130W at 2 AM MDT will
reach the coast late today, and move across Oregon tonight and
Friday morning, and into our CWA Friday. System will bring
widespread rain with 0.25" to 0.50" expected in Baker County,
northern parts of Harney and Malheur Counties, and Idaho north of
the Snake Basin. Lesser amounts are expected to the south, with
least amounts along the Nevada border. Relatively tight west-east
surface pressure gradient across southern Idaho today will produce
west winds 20 to 30 mph in and near the Magic Valley. Winds will
become east or southeast in all areas tonight ahead of the
approaching Pacific frontal system. Winds Friday will continue
light to moderate southeast, but will shift to southwest in eastern
Oregon behind the front. No thunderstorms are expected as models
keep lifted index above +2 through Friday. Thermal contrast across
the front looks weak with only 2-5 degrees cooling behind it.

.LONG TERM...Friday night through Thursday...Active storm track will
remain focused on the Pac NW through next week. This will bring a
weather system through the region every couple of days with brief
breaks in between. Friday night and Saturday will see an upper
trough exiting eastward with precipitation tapering off in valleys
on Saturday and across the mountains by Saturday night. The next
trough arrives late Sunday, exiting eastward Monday night. This is
followed by a third storm for late Wed/Thur. Each system will bring
moderate liquid/snow accumulations across higher terrain, while
lower elevations will see lighter amounts and less continuous
precipitation. Snow levels will fluctuate between 4500 and 6500 feet
MSL with passage of each system. Temperatures will be at or slightly
below normal through the period.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Thursday Thursday Night Friday
Weather: A slight chance of rain and snow showers before 7am. Patchy fog before 1pm. Otherwise, mostly sunny, with a high near 45. North wind 5 to 8 mph becoming light and variable. Chance of precipitation is 20%. Partly cloudy, with a low around 23. West southwest wind around 6 mph becoming light and variable. A chance of snow showers between 7am and 1pm, then rain and snow showers. High near 40. South wind 6 to 11 mph increasing to 12 to 17 mph in the afternoon. Chance of precipitation is 100%. New snow accumulation of less than a half inch possible.
Temperatures: 45 deg. F. 23 deg. F. 40 deg. F.
Wind direction: N WSW-variable S
Wind speed: 5-8 6 becoming light 6-11 increasing 12-17
Expected snowfall: 0 in. 0 in. less than one half in.
Granite Mountain at 7700 feet.
  Thursday Thursday Night Friday
Weather: Mostly sunny, with a high near 33. North wind 5 to 9 mph becoming calm. Partly cloudy, with a low around 22. South southeast wind 6 to 16 mph. Snow showers, mainly after noon. High near 28. Windy, with a south wind 22 to 31 mph, with gusts as high as 40 mph. Chance of precipitation is 100%. New snow accumulation of 3 to 7 inches possible.
Temperatures: 33 deg. F. 22 deg. F. 28 deg. F.
Wind direction: N SSE S
Wind speed: 5-9 becoming calm 6-16 22-31 gusts to 40MPH
Expected snowfall: 0 in. 0 in. 3-7 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.