Avalanche Advisory published on December 15, 2017 @ 6:32 am
This Avalanche Advisory expires in 16 hours, 56 minutes
This advisory is valid for 24 hours
Issued by Melissa Hendrickson - Idaho Panhandle Avalanche Center

Selkirks/Cabinets
St. Regis Basin/Silver Valley

bottom line

We have received only a trace of snow this week with contnued cold weather, with more surface faceting and isolated areas of large surface hoar buildup in frost pockets sheltered from the sun and wind. The avalanche danger is rated LOW on all slopes with generally safe riding conditions other than the thin snowpack with many obstacles.   HOWEVER......Heads up through the weekend with snow on the way covering weak facets and surface hoar abroad!

How to read the advisory


  • Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

Selkirks/Cabinets
St. Regis Basin/Silver Valley

How to read the advisory

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Above Treeline

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Near Treeline

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Below Treeline

We have received only a trace of snow this week with contnued cold weather, with more surface faceting and isolated areas of large surface hoar buildup in frost pockets sheltered from the sun and wind. The avalanche danger is rated LOW on all slopes with generally safe riding conditions other than the thin snowpack with many obstacles.   HOWEVER......Heads up through the weekend with snow on the way covering weak facets and surface hoar abroad!

  • Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Avalanche Problem 1: Loose Dry
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During the past week, the upper snowpack has become faceted, loose and weak in most areas except exposed ridgetops where you will find a 2 inch windslab. The weight of a skier or rider can easily trigger a loose dry or point release “sluff” avalanche. Loose dry avalanches will be isolated to shady, wind protected slopes steeper than 40 degrees in our mid to upper elevations. These slides are generally small and harmless but can run fast and far in steep, consequential terrain. Exercise caution on slopes harboring more than 6” of loose, sugary snow sitting on top of our slick rain crust. Use small test slopes to evaluate the ease of initiating a loose dry avalanche before committing to bigger terrain.

Avalanche Problem 2: Storm Slab
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With 1/2 to 1 foot of new expected through the weekend in the Panhandle Region, expect increasing danger a weak layers become buried.  If the snow comes as predicted avalanche danger will increase.  

recent observations

In the Selkirks 12/14 we found a 1 meter snowpack 2/3 ice topped with 2 week old storm snow that is becoming loose and sugary on the surface due to the cool weather associated with the persistent high pressure we have been in.  Unsheltered areas seem to have had some wind over the past few weeks forming a 2 inch windslab on the surface with faceting just below that slab with sheltered areas of loose faceted snow where you can get a few good turns in.  However don't expect consistent snow as a slight change in aspect can change those good turns.  There are also areas with large surface hoar in drainages that will be something to watch out for when it gets buried (possibly today 12/15).  

Similarly in the St. Regis Basin and Silver Valley Melissa reported no new snow, widespread surface hoar and near surface faceting with new snow on the way which could create some problems on these newly created persistent weak layers.

CURRENT CONDITIONS Weather observations from the Region
0600 temperature: 22 deg. F.
Max. temperature in the last 24 hours: 29 deg. F.
Average wind direction during the last 24 hours: 270
Average wind speed during the last 24 hours: 0-5 mph
Maximum wind gust in the last 24 hours: mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 14 South 34 North inches
weather

Snow likely today through the weekend with up to 6 inches by Monday morning up North with more (up to 12") expected in the Central and Southern Idaho Panhandle.  Temperatures will be in the mid and upper 20's with light winds out of West and Southwest.  Recent temperatures have been below freezing at both Lookout and Schweitzer snotels with 14 inches of snow shown at Lookout and 34 inches at Schweitzer.  

Disclaimer

Avalanche conditions change for better or worse continually. Backcountry travelers should be prepared to assess current conditions for themselves, plan their routes of travel accordingly, and never travel alone. Backcountry travelers can reduce their exposure to avalanche hazards by utilizing timbered trails and ridge routes and by avoiding open and exposed terrain with slope angles of 30 degrees or more. Backcountry travelers should carry the necessary avalanche rescue equipment such as a shovel, avalanche probe or probe ski poles, a rescue beacon and a well-equipped first aid kit.  For a recorded version of the Avalanche Advisory call (208)765-7323.

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