THIS AVALANCHE ADVISORY EXPIRED ON January 13, 2016 @ 6:45 am
Avalanche Advisory published on January 12, 2016 @ 6:45 am
Issued by George Halcom - Payette Avalanche Center
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The avalanche danger remains LOW today on non wind affected aspects. In steep upper elevation, wind loaded areas, a skier or rider could trigger  a shallow wind slab and/or get caught in a fast moving sluff. In the upper elevations the avalanche danger is MODERATE. Tonight we will likely see an increase in the avalanche danger with the forecasted snow and wind.

How to read the advisory


  • Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Avalanche Problem 1: Wind Slab
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You are most likely to find wind slabs (soft and hard) on or near ridgetops scattered from the E through the N and back to the SW aspects. Visually, the areas of wind slab  will likely have a different texture and feel hollow or punchy. In the wrong spot (shallow rocky, thin areas) these wind slabs may be resting on faceted or unconsolidated snow below and have the potential to become a nasty hard slab avalanche. This potential should be enough to keep you on your toes even though we are in a period of LOW danger. It should also be enough to keep you from skiing rocky areas that have visual evidence of recent wind effect or a much thinner snowpack. Snowmobiles are more likely to trigger this wind slab than a skier especially if you are high marking or making successive side hill runs through steep wind loaded areas. Be aware of how deep your track is digging and if you feel a sudden change in that depth, that means you have just cut through into the less consolidated snow below the more firm wind slab.

Avalanche Problem 2: Loose Dry
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A combination of a few inches of new snow earlier in the week and cold, facet forming conditions is bumping up the sluff potential right now. They  are just big enough to grab your skis and jerk you around if you stay in them.  If you are skiing or riding in steep terrain (40+ degrees), use good sluff management by performing slope cuts before committing to a steep line. If you are skiing steep, confined terrain have a plan or think about the consequences of getting pushed off course by a sluff, they have more than enough power to push you into or off of obstacles below.  

advisory discussion

Remember LOW danger does not mean no danger. Tonight we will likely see an increase in avalanche danger if we get the forecasted snow and wind. Use safe travel protocols: Travel one at a time up, down, or across slopes in avalanche terrain, exposing only one person at a time while keeping eyes on your partner. Have a plan when skiing/riding a line and share the plan with people in your group. 

 

recent observations

Surface Hoar is growing throughout the advisory area, and we need your help tracking it. It grows during clear, humid and calm conditions and once buried, it is a particularly thin, fragile and persistent weak layer in the snowpack, which accounts for a number of avalanche deaths each season. Luckily it is so fragile that it can also be destroyed by wind or dense/heavy snow (let's keep our fingers crossed). If you are out and see surface hoar let us know, it is important to track this layer as we move forward in the avalanche season.

 

 

weather

This is the last day before our mountains get a fresh start. We may see some light flurries, temperatures a bit warmer than the last few days in the upper elevations just below freezing, and some moderate winds before this evening, when a storm is to bring some much needed snow, and with it some of our serious South West winds around 40MPH.

Valley temperatures will be slightly cooler than the upper elevations as this inversion makes way for the storm.

Winter Weather Advisory in effect from January 13, 05:00 AM MST until January 13, 05:00 PM MST

 

Two-Day Mountain Weather Forecast Produced in partnership with the NOAA-NWS
McCall Airport at 5021 feet.
  Tuesday Tuesday Night Wednesday
Weather: A 20 percent chance of snow. Patchy fog before 11am. Otherwise, cloudy, with a high near 28. Light south southeast wind. Snow likely, mainly after 11pm. Cloudy, with a temperature rising to around 31 by 5am. Light south southeast wind becoming southeast 5 to 9 mph in the evening. Chance of precipitation is 70%. New snow accumulation of 1 to 3 inches possible. Snow. High near 34. South southeast wind around 8 mph. Chance of precipitation is 90%. New snow accumulation of 1 to 3 inches possible.
Temperatures: High 28 deg. F. 31 deg. F. 34 deg. F.
Wind direction: South, South East South, South East South, South East
Wind speed: Light Light to 5-9 MPH 8 MPH
Expected snowfall: 0 in. 1-3 in. 1-3 in.
Granite Mountain at 7700 feet.
  Tuesday Tuesday Night Wednesday
Weather: A 20 percent chance of snow. Cloudy, with a high near 30. Southwest wind around 17 mph. Snow likely, mainly after 11pm. Cloudy, with a low around 26. Windy, with a south southwest wind 20 to 25 mph increasing to 27 to 32 mph in the evening. Winds could gust as high as 41 mph. Chance of precipitation is 70%. New snow accumulation of 2 to 4 inches possible. Snow. High near 33. Breezy, with a southwest wind 24 to 29 mph decreasing to 18 to 23 mph in the afternoon. Winds could gust as high as 38 mph. Chance of precipitation is 90%. New snow accumulation of 3 to 5 inches possible.
Temperatures: High 30 deg. F. Low 26 deg. F. High 33 deg. F.
Wind direction: South, South West South, South West Southwest
Wind speed: 17 MPH 20-32 MPH, Gusting to 41 MPH 18-23 MPH, Gusting to 38MPH
Expected snowfall: 0 in. 2-4 in. 3-5 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.