THIS AVALANCHE ADVISORY EXPIRED ON February 14, 2019 @ 6:55 am
Avalanche Advisory published on February 13, 2019 @ 6:55 am
Issued by Dave Bingaman - Payette Avalanche Center
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The Avalanche Hazard is High today.  Heavy snowfall combined with multiple days of strong winds have created dangerous wind slabs on upper elevation, exposed slopes.  Sluffing and storm slabs are also likely on slopes over 30 degrees. Natural and Human caused avalanches are likely today.  Cornices are getting large and brittle, and will likely fail.  Travel in, or near avalanche terrain is not recommended today.

How to read the advisory


  • Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
Avalanche Problem 1: Wind Slab
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Winter storm warnings continue with another pulse of heavy snow for the next 48 hours and wind gusts already hitting 30+ on the ridges. The amount of new snow and wind effect that we have already received has created dangerous conditions on many upper elevation slopes.  Wind slabs are growing, sliding, and re-forming daily. Natural wind slab avalanches have been observed over the last few days.  Some of these slabs are easy to feel or see but some are also getting covered up with the new and wind blown snow and will be difficult to recognize. Travel in wind loaded avalanche terrain is not recommended. Check out this short video of brittle wind slabs on a SW aspect from yesterday.

Avalanche Problem 2: Storm Slab
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The amount of snow that has hit the West Central Mountains has been a big load really fast and pretty atypical for such a short time frame.  Temperature fluctuations and high winds have created slabs of various hardnesses across multiple slopes. Crusts, multiple graupple  layers and other weak layers exist within the snowpack and are buried 2-3 feet deep.  A warming trend with the possibility of rain in the lower elevations will add to the problem with warm snow falling on colder snow below.  Travel on steep slopes in the backcountry is not recommended at this time.  Wait for the snow and storms to calm down and allow the snowpack to adjust to the rapid loading. More snow today and through tonight will add to the problem. 

Avalanche Problem 3: Loose Dry
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 Yesterday we were able to trigger D1+ sluffs on slopes with small cornice bombs. We also saw significant sluff piles at the bottom of the steep terrain near Clow Point.  If you are skiing or riding slopes approaching 35 degrees you will have sluffs moving with you. Some of these may be big enough to knock you off your skis or sled and push you into trees, off rocks or into other hazards.  Be aware of terrain traps that could allow sluffs to pile up deep.

advisory discussion

PAC will issue 3 Advisories per week through the remainder of the winter as long as funding is available.

Please be aware that there are areas that are CLOSED to motorized traffic in the McCall, Goose Lake and greater West Mountains area.  Just because there are tracks in some areas, does not mean they are open.  Please respect all users and closures.  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

We had a fairly clear day yesterday in between storms and were able to see Natural Avalanches on several upper elevation, wind loaded slopes.  In addition, slopes over 35 degrees were sluffing naturally and shedding some of the new snow.   Our 600's were challenged on all but the flattest terrain and we found challenging skiing conditions on Southerly, wind exposed slopes where stiff, wind slabs were cracking under the weight of our skis and failing on isolation in our pits(see video)  Deep snow is keeping sleds off steep slopes for now and avoiding the steeps for the next few days is the best thing you could do right now.  

  

 

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: 12 deg. F.
Average wind direction during the last 24 hours: SSW
Average wind speed during the last 24 hours: 8 mph
Maximum wind gust in the last 24 hours: 23 mph
New snowfall in the last 24 hours: NA inches
Total snow depth: NA inches
weather

Very moist system will bring widespread rain and snow to the
area through tonight, with heavy snow in Baker County and in
Idaho north of the Snake Basin. Several inches of snow are
expected this morning in the western Magic Valley north of the
Snake River, and in the northern portions of harney and Malheur
Counties in Oregon. Snow levels will slowly rise, with snow
changing to rain as high as 4500 feet late today and tonight.
Precipitation will decrease in northern areas this evening,
then increase again Thursday with widespread pcpn in all areas.
Thursday will be warmer, with snow level rising to 6500 feet
north and 7000 feet south Thursday afternoon and evening.
A cold front will come through Thursday night with snow levels
lowering to valley floors again Friday, with snow showers
continuing in most areas under the cold upper trough. The
cold front may bring gusty winds Thursday night.

.LONG TERM...Friday night through Wednesday...A long wave trough
persists over the region through Sunday, stirring up light snow
showers across the region before dry northerly flow aloft briefly
provides a break in this unsettled pattern. The next system
approaches Tuesday night, once again blanketing the region with snow
showers through the extended. Temperatures will remain several
degrees below normal, dropping a few degrees lower after the weekend.

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Wednesday Wednesday Night Thursday
Weather: Snow. High near 30. South southwest wind 7 to 10 mph. Chance of precipitation is 100%. Total daytime snow accumulation of 2 to 4 inches possible Snow, mainly before 11pm. Low around 24. Light and variable wind. Chance of precipitation is 80%. New snow accumulation of less than one inch possible. A chance of snow before 11am, then rain and snow. High near 36. Light south southeast wind. Chance of precipitation is 90%. New snow accumulation of less than a half inch possible.
Temperatures: 30 deg. F. 24 deg. F. 36 deg. F.
Wind direction: SSW Variable SE
Wind speed: 7-10 Light Light
Expected snowfall: 2-4 in. 1 in. Trace in.
Granite Mountain at 7700 feet.
  Wednesday Wednesday Night Thursday
Weather: Snow. High near 21. South southwest wind 7 to 13 mph. Chance of precipitation is 100%. Total daytime snow accumulation of 7 to 11 inches possible. Snow, mainly before 11pm. Low around 19. South wind around 7 mph. Chance of precipitation is 80%. New snow accumulation of 1 to 3 inches possible. Snow. High near 30. South southeast wind around 6 mph. Chance of precipitation is 90%. New snow accumulation of 2 to 4 inches possible.
Temperatures: 21 deg. F. 19 deg. F. 30 deg. F.
Wind direction: SSW S SSE
Wind speed: 7-13(already exceeding in upper elevations) 7 6
Expected snowfall: 7-11 in. 1-3 in. 2-4 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.