THIS AVALANCHE ADVISORY EXPIRED ON March 26, 2020 @ 7:13 am
Avalanche Advisory published on March 25, 2020 @ 7:13 am
Issued by George Halcom - Payette Avalanche Center
bottom line

The Avalanche Hazard is Moderate today.  Natural avalanches are unlikely, but human triggerd avalanches are possible. You may be able to trigger isolated wind slabs in upper elevation terrain. 

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 ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Older wind slabs formed under some pretty strong winds. Yesterday afternoon we had good conditions for new wind slab development  with moderate winds and light density snow. Expect wind slabs, 3-20 inches thick, in the upper elevations, that may have formed on a crust, and in some places the wind will have scoured all the new snow off of firm Sun and temperature crusts.

If you notice any red flags like cracking or whoomphing, be cautious and turn around or find another slope or route.  Pay attention to any signs of pillows or scouring, and maintain good travel protocols, and extra cation on slopes that are wind loaded, above 7,000 feet, and steeper than 30 degrees. Wind slabs tend to form a bit below ridgelines and cornices enough to suck you into the point of no return.

 

 

advisory discussion

 

Snowmobile Parking Lots that are closed as of 3/25/2020: Wallace Lane in the New Meadows Valley, West Face, and Gordon Titus upper elevation near Brundage.

F. Wallace, Green Gate, and Brush Creeck are still open but not being plowed or maintained...If you are coming to visit the McCall, Donnelly or Cascade areas over the next few days, please be aware that we are a small, rural area with limited EMS, Medical and other resources available.  Many bars and restaurants are closed or open only for take out orders.  Both Ski Resorts are closed. We are taking the Corona Virus threat very seriously and if you are a visitor, we need you to take the precautions described by the CDC to help keep our communities safe.  You can find more info about open businesses and other community information at: https://valley-county-covid-19-response-valleycounty.hub.arcgis.com/

Also,  Please don’t ride your Snowmobile at Brundage Mountain Resort, or within the BMR permit area which includes areas adjacent to the resort. It is illegal even though the resort is closed. Also, with the lifts closed many skiers are utilizing the resort for backcountry skiing. 

recent observations

Just North of of McCall on Tuesday, near Fisher Creek saddle, our test pit on a North aspect at 7671ft showed 25cm/ 10 inches of soft dry new snow on top of a thin crust with good bonding. Total snow height was 235cm/ just a little over 7 and a half feet. Some 2-3mm graupel was mixed in the new snow. Compression tests came out hard, CT28, and broken. The crust was not noticeable on the North aspect that we skied From 8,400ft all the way down to 6,700ft. During our climb up the East face of South Bruin, we saw evidence of Southern wind transport and scouring on exposed E and SE ridges, as well as a variety of crust combinations that broke in places just under our skis. Solar crusts on E,SE, and South were noticeable and difficult to skin at times, especially where scoured by the wind.  Visibility was limited at times with cold, moderate ESE winds, and snowy conditions.

 

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: 20 deg. F.
Average wind direction during the last 24 hours: ESE
Average wind speed during the last 24 hours: 5 mph
Maximum wind gust in the last 24 hours: 16 mph
New snowfall in the last 24 hours: 3 inches
Total snow depth: NA inches
weather

 

Area Forecast Discussion
National Weather Service Boise ID
304 AM MDT Wed Mar 25 2020

.SHORT TERM...Today through Friday night...Isolated to scattered
showers will continue over southeast Oregon and southwest Idaho
through this evening under an unstable low pressure system. Snow
levels will begin around 3000 ft MSL this morning, which can lead
to a mix of rain and snow for valley locations. However, light
snow accumulations are only expected above 4000 ft MSL with these
passing showers. Today`s temperatures will likely be the coolest
day of the week, around 10 degrees below normal for this time of
year. The trough is then forecast to exit the area by Thursday,
and temperatures will gradually start to warm each day thereafter.
Clouds will increase Friday ahead of the next disturbance.

.LONG TERM...Saturday through Wednesday...An weak upper level
storm will move into the region Saturday through Sunday, spreading
showers mainly over the higher terrain. Snow levels will
initially be around 3000 ft Saturday morning, but will rise above
5000 ft during the afternoon and stay between 4000 and 5000 ft
through Sunday. Model disagreement is larger than normal after
Sunday, with the GFS maintaining strong moist WNW flow aloft while
the EC brings in a ridge. Our forecast goes more with the GFS
solution, and showers are forecast through the period, especially
in the higher terrain of the north. Temps will be slightly below
normal Saturday and Sunday, then rise to slightly above normal
Monday, and 5 to 10 degrees above normal Tuesday and Wednesday.

&&

.AVIATION...Generally VFR. Areas of mountain obscuration.
Scattered showers through today will bring local MVFR/IFR
conditions. Snow levels will be near the valley floors today, with
snow possible for all but the lowest valleys. However, no
accumulations are expected at valley airports. Surface winds: W to
NW 5-15 kts. Winds aloft at 10k ft MSL: generally W 15-30 kts.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Wednesday Wednesday Night Thursday
Weather: Widespread snow showers. Chance of snow 90 percent. Snow accumulation of 2 to 3 inches. Highs 29 to 41. Mostly cloudy with scattered snow showers in the evening, then partly cloudy with a slight chance of snow showers after midnight. Chance of snow 30 percent. Lows 12 to 23. Mostly sunny. Highs 31 to 44.
Temperatures: 29-41 deg. F. 12-23 deg. F. 31-44 deg. F.
Wind direction:
Wind speed:
Expected snowfall: 2-3 in. in. in.
Granite Mountain at 7700 feet.
  Wednesday Wednesday Night Thursday
Weather: Widespread snow showers. Chance of snow 90 percent. Snow accumulation of 2 to 3 inches. Highs 29 to 41. Mostly cloudy with scattered snow showers in the evening, then partly cloudy with a slight chance of snow showers after midnight. Chance of snow 30 percent. Lows 12 to 23. Mostly sunny. Highs 31 to 44.
Temperatures: 29-41 deg. F. 12-23 deg. F. 31-44 deg. F.
Wind direction:
Wind speed:
Expected snowfall: 2-3 in. in. in.
Disclaimer

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.