Avalanche Advisory published on February 22, 2020 @ 7:43:
This advisory is valid for 24 hours
Issued by Dave Bingaman -
bottom line

How to read the advisory

The Avalanche Hazard today is Moderate above 7000 feet on wind loaded slopes steeper than 30 degrees.  Variable winds have created small wind slabs on multiple upper elevation slopes that may be sensitive to the weight of a skier or snowmobiler.  Depending on your aspect, small loose avalanches are possible also, especially on solar slopes near exposed rocks that are warming the snowpack nearby. 


Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. Natural avalanches unlikely; human-triggered avalanches possible. Small avalanches in specific areas; or large avalanches in isolated areas.
weather

.SHORT TERM...Today through Monday night...Westerly flow aloft
will maintain the dry weather through tonight. The warming trend
will continue through Sunday ahead of an approaching cold front.
The front will be accompanied by showers, with snow showers and
light accumulations possible in the higher elevations of Baker
County and central Idaho. Little or no precipitation is expected
in the lower valleys, including the Treasure/Western Magic
valleys. Winds will increase with the arrival of the cold front
Sunday afternoon. Gusty west-northwest winds of 15-25 mph with
higher gusts are expected, and will continue through Sunday
night. Snow showers may linger in the north on Monday, otherwise
northwest flow aloft will bring dry conditions to most of
southeast Oregon and southwest Idaho. Temperatures will be several
degrees cooler. Winds will be breezy, especially east of Mountain
Home.

.LONG TERM...Tuesday through Saturday....A few snow showers will
linger across the West Central Mountains on Tuesday as the storm
system progresses towards the midwest. Thereafter, an upper level
ridge will dominate the region through the extended period,
maintaining dry conditions. Temperatures will continue to climb a
couple degrees each day through the period, becoming nearly 10
degrees above normal by next Friday.

recent observations

We toured near Lick Creek Summit yesterday and found a mostly stable snowpack.  Pit tests showed no instabilities in the upper 3 feet of the snowpack.  Through out the day we were surprised by the effect of the sun and crust that had formed on Thursday.  Despite the temps and the sun, there is still plenty of soft snow out there to be had.  We also noted several sunny slopes that were beginning to shed some snow as the day warmed and one decent sized wet, loose slide on the south aspect of South Rain Peak.

In addition, we did get a report and and some photos of a slide that was triggered by a rider on Council Mountain yesterday.  You can see that on our observation page.  We did not see any serious wind effects where we were yesterday although we did see some pluming on the highest peaks.

 

PAC volunteer Tanner Griffith checking out the snow:

South Facing terrain starting to shed some snow mid afternoon.

Avalanche Problem #1: Wind Slab

Despite the fact we haven't seen any new snow in a few days, there is still plenty of soft snow to be moved around by the wind right now.  Variable winds over the last 3 days have created small, thin wind slabs on exposed upper elevation slopes.  Snowmobilers on the East side of Council Mt. were able to isolate one of these slabs Thursday.  We observed active loading and wind affected snow on multiple aspects in nearly all of the Northern and Eastern terrain while we were out that way as well.   Yesterday, a rider got caught and partially buried on one of these wind loaded slopes.   Watch for changes in the density of the snow surface as you travel and obvious visual clues like ripples, drifts or partially covered old tracks to help identify potential wind slab or wind loaded slopes.  

Cornices are also getting large and are overhanging quite a bit in some areas.  Avoid traveling near the edges of corniced ridge lines.  Big cornices are unpredictable and can break further back than you expect.

Photo from Thursday showing active wind loading occurring.

Photo from yesterday after a snowmobiler triggered a wind slab on the same slope.

 

advisory discussion

A HUGE thanks to the board and volunteers from the Friends of the Payette Avalanche Center for putting on another great fundraiser!  Thanks also to Jughandle Parade for the tunes as well!  That was probably the biggest fundraiser ever,  thanks also to everyone that came out and supported PAC and the FPAC!

CURRENT CONDITIONS  Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 22 deg. F.
Max. temperature in the last 24 hours: 29 deg. F.
Average wind direction during the last 24 hours: E
Average wind speed during the last 24 hours: 4 mph
Maximum wind gust in the last 24 hours: 12 mph
New snowfall in the last 24 hours: inches
Total snow depth: NA inches
Two-Day Mountain Weather Forecast  Produced in partnership with the Reno NWS
For 7000-8000 ft.
  Today Tonight Sunday
Weather: Sunny, with a high near 38. Calm wind. Mostly clear, with a low around 20. Calm wind. Snow showers likely after 11am. Mostly cloudy, with a high near 36. Light southeast wind becoming south 8 to 13 mph in the afternoon. Chance of precipitation is 60%. New snow accumulation of less than one inch possible
Temperatures: 38 deg. F. 20 deg. F. 36 deg. F.
Wind direction: Calm Calm SE
Wind speed: Calm Calm 8-13
Expected snowfall: 0 in. 0 in. Trace in.
For 8000-9000 ft.
  Today Tonight Sunday
Weather: Sunny, with a high near 29. South southwest wind 3 to 6 mph. Partly cloudy, with a low around 17. Calm wind becoming south 5 to 7 mph after midnight. Snow showers likely after 11am. Mostly cloudy, with a high near 26. South wind 7 to 12 mph increasing to 13 to 18 mph in the afternoon. Chance of precipitation is 70%. New snow accumulation of 1 to 3 inches possible.
Temperatures: 29 deg. F. 17 deg. F. 26 deg. F.
Wind direction: SSW S S
Wind speed: 3-6 5-7 13-18
Expected snowfall: 0 in. 0 in. 1-3 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.