Avalanche Advisory published on March 11, 2020 @ 7:03 am
Issued by George Halcom - Payette Avalanche Center
bottom line

The Avalanche Hazard will start out Low this morning and increase to Moderate this afternoon. The potential for natural wet, loose avalanches and wet sluffs will be the main concern this afternoon on steep slopes getting direct Sunlight.  

How to read the advisory

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

Today the Sun, and warmer temperatures, may produce wet-loose slides and roller balls. Be cautious on steep slopes getting direct sunlight especially this afternoon. Rocky outcrops are the most likely areas to shed snow. If you start seeing rollerballs forming, choose another slope aspect that is not getting heated by the Sun. 



recent observations

Yesterday, North of Brundage Ski Resort, on Sgt's mountain, the Sun was lighting up the fresh crop of large Surface hoar that formed on the surface of the snow. Travel was easy and smooth on about 6-10 inches of new snow on top of a crust on all but upper due Northern aspects of Sgts mountain. The numerous mit pits showed good bonding of the new snow on the crust. 

Around 3 pm, the Sun felt very warm, but slopes facing to the North stayed cool above 7,000 feet with a little help from the wind.


Surface hoar and graupel was widespread, and will likely get destroyed in the next few days, but we will see how well the next layers of snow Friday night will bond. 

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 24 deg. F.
Max. temperature in the last 24 hours: 26 deg. F.
Average wind direction during the last 24 hours: E
Average wind speed during the last 24 hours: 17 mph
Maximum wind gust in the last 24 hours: 17 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: NA inches


Area Forecast Discussion
National Weather Service Boise ID
257 AM MDT Wed Mar 11 2020

.SHORT TERM...Today through Friday night...Sunny and several
degrees warmer today under dry wnw flow aloft. Clear and cool
tonight except partly cloudy with a slight chance of snow
showers in the central idaho mountains. Upper trough from the
north will bring breezy and cooler weather Thursday with skies
becoming sunny again. Clouds will increase from the northwest
Friday as a stronger upper trough approaches. This will lead
to snow showers in northern areas and a chance of rain and snow
showers in southern areas Friday night.

.LONG TERM...Saturday through Wednesday...An upper low will
progress southward along the Pacific Coast this weekend, causing
widespread precipitation over the Intermountain West. Temperatures
will fall 5-8 degrees below normal behind a cold front on Saturday,
causing snow levels to drop near/to valley floors. Beyond Sunday,
the system is expected to progress eastward across the Great Basin,
stirring up snow showers across the region through Wednesday.


.AVIATION...Mostly VFR. Isolated MVFR/IFR conditions due to
fog/stratus. Surface winds: generally SE to SW less than 10 kts,
becoming NW 5-15 kts with gusts up to 20-25 kts in the afternoon.
Winds aloft to 10k feet MSL: westerly 20-25 kts.


Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Wednesday Wednesday Night Thursday
Weather: Mostly sunny, with a high near 44. Calm wind becoming west southwest around 6 mph in the afternoon. Partly cloudy, with a low around 16. West wind around 5 mph becoming calm in the evening. Sunny, with a high near 37. Calm wind.
Temperatures: 44 deg. F. 16 deg. F. 37 deg. F.
Wind direction: WSW West becoming Calm Calm
Wind speed: 6 5-0 0
Expected snowfall: 0 in. 0 in. 0 in.
Granite Mountain at 7700 feet.
  Wednesday Wednesday Night Thursday
Weather: Mostly sunny, with a high near 29. South southwest wind 8 to 10 mph. Partly cloudy, with a low around 13. West northwest wind around 9 mph. Sunny, with a high near 25. North wind 5 to 7 mph becoming light and variable in the afternoon.
Temperatures: 29 deg. F. 13 deg. F. 25 deg. F.
Wind direction: S WNW N-variable
Wind speed: 8-10 9 5-7 becoming light
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.