THIS AVALANCHE ADVISORY EXPIRED ON January 22, 2017 @ 6:43 am
Avalanche Advisory published on January 21, 2017 @ 6:43 am
Issued by Kent May - Payette Avalanche Center
bottom line

The avalanche danger is CONSIDERABLE above 6000 feet.. Our most recent storm cycle put down 18-21 inches of new snow that fell on a variety of old snow surfaces including well developed Surface HoarNear Surface facets and firm crusts.  In addition, a fresh crop of wind slabs will be found near the ridge tops on leeward slopes. Small to medium sized, human triggered avalanches are likely today.

How to read the advisory


  • Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Persistent Slab
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A relatively widespread layer of Surface Hoar and Near Surface Facets is now lying below the new snow.  We found this layer on Thursday 15-18 inches down in the middle elevations and in higher areas that were protected from the winds that accompanied this last storm cycle. Surface Hoar and faceted snow layers are responsible for more avalanche accidents and fatalities than all other types of avalanches combined.  This layer failed in many steep areas naturally as the new snow came in but is waiting for a trigger in many more.  This is a very tricky layer to predict or forecast for due to the variability and the uncertainty of where you will find it in the snowpack and throughout the mountains right now.  The only way you will know for sure is to dig in to the snow and look for the obvious grey line in the snow.  Whumphing or collapsing of the snowpack will let you know that you are in an area with buried surface hoar or faceted snow.  With this kind of variability, you will need to dig in lots of places as you travel.  Hand pits in lots of locations or 5 minutes with your shovel could save your life today.

The photos show one of the many small avalanches we saw Thursday along the Goose Creek Rd and a close up of the surface hoar layer at the height of the saw.  This type of problem tends to linger for awhile.

 

                                   

Avalanche Problem 2: Wind Slab
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A fresh crop of wind slabs was created in the upper elevations with the last storm cycle and winds in the upper 20 mph range common throughout most of the area.  The winds have swirled across the bottom of the compass from East to South West creating the possibility of 1-3 foot deep wind slabs on the northern portion of the compass as well as East and West aspects.  These slabs may be resting on old wind slabs, a layer of surface hoar, or other faceted (loose grained) snow or on firm crusts.  Pay attention to the obvious signs of wind affected snow, rounded, sculpted, drifted or pillowy looking snow will let you know right where the wind deposited snow piled up.  Hollow sounding or feeling snow should tell you to find a different slope as well.

advisory discussion

Snowmobiler/Snowbiker Travel Restrictions:  a quick reminder that the Granite Mountain Area Closure is now in effect.  In addition there are other areas on the Payette National Forest that are CLOSED to snowmobile traffic including Jughandle Mt east of Jug Meadows, Lick Creek/Lake Fork Drainage (on the right side of the road as you are traveling up canyon), and the area north of Brundage Mt Ski area to junction "V" and along the east side of Brundage snd Sargeant's Mts. with the exception of the Lookout Rd( junction "S").  Please respect these closures and other users recreating in them.  Winter Travel Map(East side)

Remember your information can save lives. If you see anything we should know about, please participate in the creation of our own community avalanche advisory by submitting snow and avalanche conditions. It's okay if you leave some fields blank, just fill out what you know and/or submit photos. You can  also email us at  forecast@payetteavalanche.org.

The Friends of the Payette Avalanche Center (FPAC) needs YOU! We are in desperate need of more user support and financial assistance. The avalanche forecast is not a guaranteed service, and is in jeopardy of dwindling down to only a couple of days a week in the near future. Please help if you can by clicking the DONATE tab above. If you value this life saving information, make a donation or help the FPAC in raising funds for the future.

CURRENT CONDITIONS Today's Weather Observations From the Granite Weather Station at 7700 ft.:
0600 temperature: 18 deg. F.
Max. temperature in the last 24 hours: 18 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 3 mph
Maximum wind gust in the last 24 hours: 6 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: inches
weather

No new snow overnight. Today expect scattered snow showers, with cloudy skies and a high near 24. South southwest wind 10 to 15 mph. Chance of precipitation is 50%. Total daytime snow accumulation of around an inch possible.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Saturday Saturday Night Sunday
Weather: Scattered snow showers, mainly before 11am. Cloudy, with a high near 31. South wind 3 to 5 mph. Chance of precipitation is 40%. Total daytime snow accumulation of less than one inch possible. A chance of snow showers before 11pm, then a chance of snow after 11pm. Cloudy, with a low around 20. Southeast wind around 5 mph. Chance of precipitation is 40%. New snow accumulation of less than a half inch possible. Snow, mainly after 11am. High near 32. South southeast wind 6 to 8 mph. Chance of precipitation is 80%. New snow accumulation of 1 to 2 inches possible.
Temperatures: high 31 deg. F. low 20 deg. F. high 32 deg. F.
Wind direction: south southeast south-southeast
Wind speed: 3-5 5 6-8
Expected snowfall: Less than 1 in. less than 0.5 in. 1-2 in.
Granite Mountain at 7700 feet.
  Saturday Saturday Night Sunday
Weather: Scattered snow showers. Cloudy, with a high near 24. South southwest wind 10 to 15 mph. Chance of precipitation is 50%. Total daytime snow accumulation of around an inch possible. A chance of snow showers before 11pm, then a chance of snow after 11pm. Cloudy, with a low around 18. South southwest wind 11 to 16 mph. Chance of precipitation is 50%. New snow accumulation of less than one inch possible. Snow, mainly after 11am. High near 27. Wind chill values between -1 and 9. Windy, with a south wind 21 to 30 mph, with gusts as high as 40 mph. Chance of precipitation is 90%. New snow accumulation of 1 to 3 inches possible.
Temperatures: high 24 deg. F. low 18 deg. F. high 27 deg. F.
Wind direction: south-southeast south-southeast south
Wind speed: 10-15 11-16 21-30 gusting 40
Expected snowfall: 1 in. Less than 1 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.