THIS AVALANCHE ADVISORY EXPIRED ON January 17, 2018 @ 5:01 am
Avalanche Advisory published on January 16, 2018 @ 5:01 am
Issued by Ben Bernall - Kootenai National Forest

Kootenai

bottom line

The upper elevations above tree-line are still harboring a dense slab of snow from the last storm cycle.   Stability tests are showing that the snowpack is strengthening; but, large open slopes and wind loaded terrain should be approached with caution.  

How to read the advisory

The upper elevations above tree-line are still harboring a dense slab of snow from the last storm cycle.   Stability tests are showing that the snowpack is strengthening; but, large open slopes and wind loaded terrain should be approached with caution.  

3. Considerable

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Above Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

2. Moderate

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Near Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

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Below Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
    Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Persistent Slab
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Recent snow from the last storm cycle came in warm and formed a dense slab in most locations above 5,000'. It overlies multiple interfaces including buried surface hoar 28" below the surface in some locations.  Use caution before committing to steep slopes and be mindful of rising temperatures on any aspect recieving sun.  Rapid changes in temperature or solar radiation will weaken these slabs and increase the potential for avalanches.  

Avalanche Problem 2: Loose Wet
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Mountain weather forecasts are showing the potential for warm temps and some potential sunny days.  Exposed solar aspects have real potential to release in the coming days.  Potential exists for loose wet snow avalanches to step down to deeper weak layers and release larger slabs in the process.  Pay attention to changing conditions (rising temperatures, rollers and small point releases),  avoid being on steep, open slopes when exposed to the sun.  This aspect of the forecast will be dynamic in nature from day to day, and worth paying close attention to.

Avalanche Problem 3: Wind Slab
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This problem is isolated to the highest terrain on exposed features where southwest winds from the last storm cycle have loaded leeward slopes.  Look for changes in density of surface snow and pillow like formations.  

advisory discussion

Join us January 26th and 27th for a free Intro to Avalanches Course hosted by David Thompson SAR.  This will begin on Friday night at the SAR Barn in Libby (7PM) for a classroom session. Then proceed to Keeler-Rattle warming hut for a day of field instruction.  For more info contact SAR Mountian Unit Leader Terry Crooks at 293-1618.

recent observations

Stability tests performed in the Eastern Cabinets are showing  a strengthening snowpack with failures declining in reactivity and likelihood of propagation.  Primary concerns at this time are the potential to trigger a slide on steep, open terrain at the uppermost elevations.  There are still multiple structural weaknesses within the snowpack, though they are not very reactive in stability tests they could wake up with sun, rising temperatures or the release of a smaller wind slab.

Weather and CURRENT CONDITIONS
weather summary
Backcountry Forecast from NWS Missoula issued:
400 AM MST Tue Jan 16 2018
DISCUSSION: Expect an increase in clouds this afternoon ahead of a 
weak weather system that will last through Tuesday night. Light
snow at best is expected. Expect dry weather Wednesday with some
warmer temperatures.

A more vigorous storm system will impact the entire northern
Rockies late Wednesday night through Thursday night. Snow levels
will start off pretty warm through Thursday morning, above
6000-6500 feet. A cold front will move through Thursday afternoon
and lower snow levels to near valley floors. Several inches of
snow are likely in the mountains Thursday afternoon and night. 

Kootenai:
--------------------------- 5000-7000 FT ----------------------------
                      Today        Tonight      Wed      
Cloud Cover           50%          85%          80%      
Hi/Lo Temps           30 to 33     23 to 26     32 to 35 
Winds(mph)            S  8         SW 11        S 10G24  
Precip Chc            30           20           0        
Precip Type           snow         snow         none     
Liquid Amt            0.02         0.02         0.00     
Snow Ratio(SLR)       10:1         13:1         0        
Snow Amt(in)          0            1-3          0        
Snow Level            2000         3500         3000     
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.