THIS AVALANCHE ADVISORY EXPIRED ON January 13, 2018 @ 6:22 am
Avalanche Advisory published on January 12, 2018 @ 6:22 am
Issued by Jeff Thompson - Idaho Panhandle Avalanche Center

Kootenai
Selkirks/Cabinets
St. Regis Basin/Silver Valley

bottom line

The recent storm has left more than 2 feet of snow in most locations. The new snow fell on top of a couple weak layer resulting in dangerous avalanche conditions.  Travel is not recommended in avalanche terrain.  Storm slabs are usually the weakest in the 24-48 hours after a storm. Yesterday, we found the storm slab was not bonding well to the old snow underneath.  Thank you to Schweitzer Mountain for sponsoring our forecast today! 

How to read the advisory

Kootenai
Selkirks/Cabinets
St. Regis Basin/Silver Valley

How to read the advisory

The recent storm has left more than 2 feet of snow in most locations. The new snow fell on top of a couple weak layer resulting in dangerous avalanche conditions.  Travel is not recommended in avalanche terrain.  Storm slabs are usually the weakest in the 24-48 hours after a storm. Yesterday, we found the storm slab was not bonding well to the old snow underneath.  Thank you to Schweitzer Mountain for sponsoring our forecast today! 

4. High

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Above Treeline
Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.

4. High

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Near Treeline
Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.

3. Considerable

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Below Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
    Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
Avalanche Problem 1: Storm Slab
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The new snow fell on a very weak layer causing dangerous avalanche conditions. There is a buried surface hoar and rain crust underneath the new snow that is causing a weakness at the interface with the storm slab.

Avalanche Problem 2: Persistent Slab
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Besides the new snow problem, the snowpack has multiple persistent weak layers buried.  The storm slab is the biggest concern right now, but the buried persistent faceted layers should be considered as well when analyzing the snowpack.

Avalanche Problem 3: Deep Slab
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Don't forget about the buried November crust. There are bigger concerns near the surfce of the snowpack but an avalanche could easily step down to this layer with the right trigger

recent observations

Please submit observations to IPAC. We want to know whats going on out there! Our hearts and prayers go out to the family and friends of the recent avalanche victims.  There have been multiple avalanche fatalities in the surrounding area. We recommend staying off of avalanche terrain until things settle down a little. Stay safe out there! 

Weather and CURRENT CONDITIONS
weather summary

This winter storm will be heading out by mid day tomorrow.  Look for a few lingering inches of accumulation. It looks to be favoring the the southern zone. The Silver valley and Lookout Pass area could see a couple more inches before this storm finally pushes out.  Don't expect much more accumulation in the Selkirks, Purcells or Cabinet mountains.

Weather observations from the Region
0600 temperature: 27 deg. F.
Max. temperature in the last 24 hours: 33 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 15 mph
Maximum wind gust in the last 24 hours: 31 mph
New snowfall in the last 24 hours: 9 inches
Total snow depth: 150-230 cm inches
Two-Day Mountain Weather Forecast Produced in partnership with the Spokane NWS
For 2000 ft. to 4000 ft.
Friday Friday Night Saturday
Weather: Snow / Rain Snow / Rain Snow / Rain
Temperatures: 35 deg. F. 33 deg. F. 37 deg. F.
Wind Direction: SW SW SW
Wind Speed: 5-7 3-5 3-5
Expected snowfall: >1'' in. >1'' in. >1'' in.
For 4000 ft. to 6000 ft.
Friday Friday Night Saturday
Weather: Snow Snow Snow
Temperatures: 32 deg. F. 29 deg. F. 33 deg. F.
Wind Direction: SW SW SW
Wind Speed: 8-10 9-11 8-10
Expected snowfall: 1-4'' in. 1-3'' in. 1-2'' in.
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.