Avalanche Advisory published on January 30, 2019 @ 7:04 am
Issued by George Halcom - Payette Avalanche Center
bottom line

The Avalanche Hazard is Low. Shallow wind slabs are possible near ridge tops and on exposed terrain.  Don't 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.

How to read the advisory

  • Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Avalanche Problem 1: Wind Slab
  • Character ?
  • Aspect/Elevation ?
  • Likelihood ?
    Very Likely
  • Size ?
    Very Large

Wind Slabs have stabilized for the most part, but should still be considered, especially if you are skiing or riding in steep, confined or consequential terrain where a small slab could push you into or over downhill hazards. Most of the upper elevation snow has a punchy and or firm feeling. 

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. 

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 will issue 3 Advisories per week.

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.  




recent observations


Yesterday, we toured the Lick Cr Drainage near Beaverdam Peak. The Sun and variable wind, along with temperatures and time, have stabilized the snowpack. Currently there are challenging snow surfaces everywhere, and soft cold powder in lower in elevations, and or areas protected from the Sun and winds. The Sun has put a stout crust on Southern aspects, sometimes visible miles away. High Northerly terrain took a heavy beating from unusual wind patterns and is only barely skiable in places where the wind scoured and or pounded the snow into a stiff board that begs for sharper edges.  Softening of the snow surface is somewhat limited to South aspects during the day.  Snowmobiling off trail could be challenging if you need to initiate a side hill on firm Sun or wind crust.

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 17 deg. F.
Max. temperature in the last 24 hours: 36 deg. F.
Average wind direction during the last 24 hours: E
Average wind speed during the last 24 hours: 2 mph
Maximum wind gust in the last 24 hours: 10 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: NA inches


Area Forecast Discussion
National Weather Service Boise ID
336 AM MST Wed Jan 30 2019

.SHORT TERM...Today through Saturday Night...Dry through Friday as
a ridge slowly moves across the area while a cutoff low tracks
across Southern California. Temperatures should warm slightly as
we get into southwest flow ahead of the next trough. That trough
approaches on Friday, and by afternoon winds will have picked up
in most areas, and showers may start to move into the Eastern
Oregon zones. Models are still splitting this system, but most
models now have the southern piece quite a bit further north,
bringing much more precip to the area on Saturday. Still some
model spread here, and exact track of splitting systems is
typically very difficult, but raised precip chances on Saturday a
bit to reflect the trend. If this comes to pass, much of Saturday
would still be on the warm side of the trough, with snow levels
around 5kft, with a cold front coming through Saturday night.
Thus, mostly valley rain, and mountain snow with the heaviest
precip on Saturday, and then precip tapering off most areas
Saturday night, but changing to snow in the valleys as the cold
front goes by. Hard to count on these kinds of details that far
out - but the general trend in the forecast fits this scenario.

.LONG TERM...Sunday through Wednesday...Active weather pattern will
continue through the extended period as a series of weak troughs
move through. There is quite a bit of spread in the intensity of the
next trough for Sunday into Monday with the stronger and colder
ECMWF being the outlier. However, all model guidance is in agreement
with at least a trough passage Sunday/Monday. Widespread
precipitation is still expected for all areas. Snow levels remain
between 3500-4500 ft which would bring rain for much of our valley
locations. The upper level ridge rebuilds over the region Tuesday
into Wednesday ahead of another upper level system off the west
coast. Temperatures will remain above normal through much of the
period falling to near normal by Tuesday.

.AVIATION...VFR. Occasional high clouds. Surface winds light and
variable. Winds aloft at 10k feet MSL northwest 10-20 kts.

.AIR STAGNATION...Little change in inversions expected until
Friday, with slightly lower mixing heights over Oregon vs Idaho.
Increased winds and mixing on Friday should improve the situation,
with precipitation late Friday night and Saturday wiping out any
remaining inversions.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Wednesday Wednesday Night Thursday
Weather: Patchy fog before 11am. Otherwise, sunny, with a high near 31. Calm wind. Mostly clear, with a low around 14. Calm wind. Sunny, with a high near 35. Calm wind.
Temperatures: 31 deg. F. 14 deg. F. 35 deg. F.
Wind direction: Calm Calm Calm
Wind speed: 0 0 0
Expected snowfall: 0 in. 0 in. 0 in.
Granite Mountain at 7700 feet.
  Wednesday Wednesday Night Thursday
Weather: Sunny, with a high near 27. South southwest wind around 6 mph. Mostly clear, with a low around 18. South southeast wind around 7 mph. Mostly sunny, with a high near 30. South wind around 8 mph.
Temperatures: 27 deg. F. 18 deg. F. 30 deg. F.
Wind direction: SSW SSE S
Wind speed: 6 7 8
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.