Avalanche Advisory published on January 28, 2019 @ 6:58 am
Issued by George Halcom - Payette Avalanche Center
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The Avalanche Hazard is MODERATE in upper elevation wind loaded terrain. Shallow wind slabs are possible near ridge tops and on exposed terrain.  Small, loose/dry snow avalanches or sluffs are also possible in shady, very steep, wind/sun protected terrain.  Roller balls and other types of loose/wet activity will increase throughout the day on slopes affected by warming temperatures and direct solar effect.  Use safe travel protocols, and be aware of changes in the snow pack on different aspects. 

How to read the advisory

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

Wind Slabs are still a problem to consider if you are skiing or riding in steep, exposed terrain right now. Observations from PAC staff and others throughout the area still point to a small but nagging problem of punchy feeling wind slabs in terrain that has been affected by the winds.  These slabs have strengthened over the last week but are still something to consider if you are in steep, confined or consequential terrain where a small slab could push you into or over downhill hazards.

Pay attention to wind stiffened snow near the ridge tops on the northern exposures today or places that show obvious wind effect in the form of ripples or small pillows. In addition, other steep slopes may produce small loose avalanches or sluffs.  As you move into shaded, sun protected, steeper terrain, keep in mind that you are likely to see dry snow moving with you.  Even small sluffs can steer you where you don't want to go especially in tight, confined terrain. 

Sunny aspects have been shedding snow as well.  Temps will be a little cooler today at the upper elevations, so the activity should be much less than the last couple of days. Roller ball and small, loose/wet activity will be possible on steep southerly aspects as the sun hits them.

Just because the snow pack is strengthening does not mean you should let your guard down, be smart, use safe travel protocols including 1 at a time on steep terrain and be aware of changes in the snow pack throughout the day on different aspects.

advisory discussion

PAC should be back to a normal forecast schedule next week with the end of the government shutdown.

SNOWMOBILERS- please be aware that there are areas that are CLOSED to motorized traffic in the McCall  and greater West Mountain area.  See the Payette Winter Travel Maps for clarification.  Both the East and West maps can be downloaded on the Avenza app on your phone or are available at trailheads and local shops.   IT IS YOUR RESPONSIBILITY TO KNOW WHERE YOU ARE AND WHERE THESE CLOSURES EXIST.  

Over the last week, George and I witnessed several incursions in areas that are closed,  including this area near Maloney Lake where we were skiing on our day off.  We also witnessed violations yesterday in the Brundage Cat Ski Terrain.  If we don't respect area closures and other recreationists using these areas, we will see more regulations , enforcement and more negative user encounters.  Use the map, use your brain and respect closures where they exist. Share the snow and show respect when you encounter ski tracks in the backcountry, there is plenty of snow out there for all of us.

Photos show sled tracks into closure in the upper SF of Lake Fork.  The pics also show our ski tracks that were there when the incursion happened.  Our personal sleds were parked just to the right of the tracks for the entire day while we were touring in the non-motorized closure.  Good backcountry etiquette is to avoid slopes where skiers or other users are playing.  It is pretty hard to imagine that a group of 6 folks could be that unaware of basic  backcountry courtesy...

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 15 deg. F.
Max. temperature in the last 24 hours: 35 deg. F.
Average wind direction during the last 24 hours: NW
Average wind speed during the last 24 hours: 7 mph
Maximum wind gust in the last 24 hours: 32 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 66 inches

Area Forecast Discussion
National Weather Service Boise ID
335 AM MST Mon Jan 28 2019

.SHORT TERM...Today through Thursday Night...For the most part, a
ridge aloft continues to dominate through Thursday. A wave passing
east of the area today increases the easterly pressure gradient,
which will bring an increase in east winds in the Snake Plain and
a few degrees of cooling, but not much else. On Tuesday a weak
system starting to break under the ridge will bring a few more
clouds to central Oregon. Late Wednesday another, stronger, system
breaks under the ridge, but is moving toward southern California.
Again, the main impact will be a few clouds, and a slight chance
of showers, in central Oregon. By late Thursday the ridge moves
east of the area, and southwest flow starts to increase, with
showers pushing into southeast Oregon toward Friday morning.

.LONG TERM...Friday through Monday...Next upper level system will
move into the Intermountain West on Friday bringing our first chance
for precipitation. Models show the trough splitting as it moves
inland which, if this trend continues, will limit precipitation
amounts across the forecast area. Snow levels increase to around
4500-5000 feet by Friday night. A trailing, colder trough will
follow for Sunday. Temperatures are above normal through Saturday,
trending toward normal on Sunday with the cooler system. Timing
of this system is varied between the models so confidence remains

.AVIATION...VFR under mostly clear skies. Local IFR in valley fog
near KMYL will burn off by 18z Monday. Surface winds 10-15 kts
today with gusts up to 25 kts especially between Mountain Home and
Twin Falls. Winds aloft at 10k ft MSL: northwest 25-35 kts.

.AIR STAGNATION...Not much change until Friday. Mixing heights to
remain around 1-1.5 kft AGL over Oregon, and 2-2.5 kft AGL over
Idaho. Transports winds generally less than 10 mph, leading to
poor ventilation. The Snake Plain of Idaho will see increased
east transport winds of 10-20 mph today, but decreasing again
overnight. Inversions should mix out in all areas on Friday as a
storm system moves in from the west.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Monday Monday Night Tuesday
Weather: Patchy fog before 11am. Otherwise, sunny, with a high near 34. Northeast wind around 5 mph becoming calm in the morning. Mostly clear, with a low around 11. Calm wind. Sunny, with a high near 32. Calm wind.
Temperatures: 34 deg. F. 11 deg. F. 32 deg. F.
Wind direction: NE Calm Calm
Wind speed: 5 0 0
Expected snowfall: 0 in. 0 in. 0 in.
Granite Mountain at 7700 feet.
  Monday Monday Night Tuesday
Weather: Sunny, with a high near 28. Northeast wind 5 to 10 mph becoming south in the afternoon. Mostly clear, with a low around 14. South southeast wind around 6 mph. Sunny, with a high near 28. East wind around 5 mph becoming calm in the morning.
Temperatures: 28 deg. F. 14 deg. F. 28 deg. F.
Wind direction: NE becoming South SSE E
Wind speed: 5-10 6 5
Expected snowfall: 0 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.