THIS AVALANCHE ADVISORY EXPIRED ON March 9, 2019 @ 4:59 am
Avalanche Advisory published on March 8, 2019 @ 4:59 am
Issued by Ben Bernall - Kootenai National Forest

Kootenai

bottom line

With a modest dose of fresh snow and strong south west winds we will continue to list WINDSLAB as the main concern. Expect to find dense slabs of snow near ridgelines and steep rolls. Watch for shooting cracks in the surface of the snowpack and be very wary of steep, unsupported terrain on north and easterly aspects when dropping off of ridglelines this weekend. 

How to read the advisory

With a modest dose of fresh snow and strong south west winds we will continue to list WINDSLAB as the main concern. Expect to find dense slabs of snow near ridgelines and steep rolls. Watch for shooting cracks in the surface of the snowpack and be very wary of steep, unsupported terrain on north and easterly aspects when dropping off of ridglelines this weekend. 

2. Moderate

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

2. Moderate

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

1. Low

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Below Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
    Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Wind Slab
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    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Fresh snow and stout winds out of the southwest yesterday created dense slabs of reactive snow just below ridgeline and steep rolls on north and easterly aspects. These slabs were mostly isolated to these locations and consequently small in size. It is very possible you will trigger something bigger if high-marking or dropping into steep and open terrain on these aspects. Use caution and watch for shooting cracks, and changes in surface density to alert you to these slabs. Yesterday they were making themselves obvious as can be seen in the photos below.

advisory discussion

So, lets start with the good news. 

The riding and skiing conditions are fantastic and generally the snowpack is quite stable across the area. Snowpack tests have produced pretty consistent results and shown the weak layers within the snowpack are unlikely to propagate into a slab avalanche. Yesterday we found one anomaly at 6,400' on a NE aspect that propagated with hard force, it did not propagate in the second test or in adjacent pit. This is really a good reminder of the fact that snow varies widely across aspects and elevations and you will not always see everything that is going on below the surface. SO, again the best way to deal with these unknowns is to be prepared and practice smart travel habits.

Fresh snow and strong winds! On the trip up yesterday in the East Cabinets we had moderate winds out of the North which switched mid-day to strong out ot the South and West. The loose, fresh snow was rapidly transported and forming fairly reactive slabs near ridgeline. Additional observations from the West Cabinets reported similiar conditions in Keeler Creek. The 6" of new snow was poorly bonded to the older snow but it was not slabby or likely to be a concern unless you are in an area where the wind worked its evil magic. In steep terrain you may get some light surface sloughing out of this new snow. as well.  Lastly, hard to believe but it is now March. When the sun comes out (which it may this weekend) it will have some energy that we haven't seen in a while. Expect the new snow to form small wet slides on southerly aspects in steep terrain. Likely to be pretty harmless except in areas where they can entrain you and push you into trees or cliffs.

 

Weather and CURRENT CONDITIONS
weather summary
Backcountry Forecast from NWS Missoula issued:
510 AM MST Fri Mar 8 2019

DISCUSSION: Occasional snow showers are anticipated today and 
Saturday, most numerous in the afternoons with only an inch or two
possible each day. Westerly winds on the terrain today are 
expected to diminish for Saturday. Skies clear with a dry period 
Sunday and Monday. Another weak weather system Tuesday into 
Wednesday will once again produce light to moderate snow 
accumulations. Temperatures will remain at below normal levels 
into next week. 

Kootenai:
--------------------------- 5000-7000 FT ----------------------------
                      Today        Tonight      Sat      
Cloud Cover           65%          70%          55%      
Hi/Lo Temps           20 to 30     9 to 14      20 to 30 
Winds(mph)            SW  8G24     SW 10G21     SW  7    
Precip Chc            30           20           0        
Precip Type           sno/shr      snow         snow     
Liquid Amt            0.02         0.01         0.00     
Snow Ratio(SLR)       19:1         19:1         20:1     
Snow Amt(in)          0-1          0            0        
Snow Level            500          0            0        
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.