THIS AVALANCHE ADVISORY EXPIRED ON February 7, 2018 @ 4:47 am
Avalanche Advisory published on February 6, 2018 @ 4:47 am
Issued by Ben Bernall - Kootenai National Forest

Kootenai

bottom line

Use caution on steep slopes above 6,000' in elevation as recent storm snow has yet to fully bond to the existing snowpack.  A slide triggered on this storm snow also retains the possibility of steeping down to deeper weak layers at this elevation as well.

How to read the advisory

Use caution on steep slopes above 6,000' in elevation as recent storm snow has yet to fully bond to the existing snowpack.  A slide triggered on this storm snow also retains the possibility of steeping down to deeper weak layers at this elevation as well.

2. Moderate

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

1. Low

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

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: Storm Slab
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On Sunday February 4th we recieved a decent shot of moisture that came in warm and fell mostly as rain below 6,000' across the area.  At the upper most elevations of the Kootenai this moisture added yet another layer of storm snow to the variable sandwich of layers in the highest terrain.   Use caution on steep slopes (over 30°) above 6,000' in elevation on all aspects.  As you gain altitude this week, stop, observe and pay attention to changing conditions at upper elevations.

Avalanche Problem 2: Persistent Slab
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Over the past couple of weeks the temperatures and moisture patterns have been in a constant see-saw motion that has effectively stabilized the snow pack at lower elevations.  At upper elevations it has created multiple layers of snow that vary in density.  Many of these layers are producing clean shears.  Although they are proving to be fairly strong and stubborn they could release and result in a large avalanche with the right trigger.  A slide in the upper layer of storm snow or a rider launching off a cornice may be all thats required to trigger one of these deeper layers.  Again, use caution at elevations above 6,000' and constantly re-evaluate the snow conditions as you climb or change aspects.

recent observations

If one were to sit down and take a look at area snotel sites right now you will observe that we have had multiple days where the temperatures have climbed above the freezing mark, even Hawkins Lake Snotel that sits at 6,400' has climbed up into the mid-thirties.  On Sunday the area picked up a decent shot of moisture with Bear Mt. picking up close to 1" of SWE (snow water equivalent).  The story here really comes down to the fact that as we go through these warm spells in the mountains the snowpack is becoming temporarily unstable, then locking back together as the temperatures drop.  What riders need to keep in mind right now is that it is easy to get lulled into a false sense of security because of the good stability at lower elevations, we also need to keep in mind that conditions could change drastically at higher terrain. It is important to pay close attention to the weather as we go through these "spring-like" variations in temperature and high elevation rain.

Feel free to send me your observations as you get out and play.  Even if you rode all day and saw no avalanche activity that is still useful to me.  Observations can be kept anonymous, just let me know what you are seeing out there with a quick right-up on the conditions.  Send them to bbernall@fs.fed.us

 

Weather and CURRENT CONDITIONS
weather summary
Backcountry Forecast from NWS Missoula issued:
400 AM MST Tue Feb 6 2018

DISCUSSION: Unsettled, moist northwesterly flow will dominate the
next two days or so across all of the Northern Rockies. QPF
amounts will be light but persistent, aside from the Southern 
Swans and, to a lesser degree, the northern Bitterroots. Here we
expect slightly higher amounts to fall, given the favored upslope
component. Still, not as bad as previous days. Winds will also be
much more behaved, but this will all come to a screeching halt
Thursday. 

Another arctic boundary will become a multi-day nuisance, 
particularly across the NW and along the Divide (very similar to 
the last event). Interestingly enough, this upcoming storm has 
sped up in the latest forecast model runs. As such, timing the 
onset of the arctic will once again be a challenge, but a 
challenge we are up for! What we know now: high SWE is likely for
the Whitefish, Glacier, northern Swans, and Rattlesnake. Winds 
will increase areawide into the 50 mph range and higher once 
again, creating difficulties of its own. More details will become 
available in the coming days, so stay tuned.
--Allegretto

Kootenai:
--------------------------- 5000-7000 FT ----------------------------
                      Today        Tonight      Wed      
Cloud Cover           80%          80%          95%      
Hi/Lo Temps           28 to 34     23 to 29     33 to 37 
Winds(mph)            W  9         SW 10G23     SW 12G22 
Precip Chc            0            50           50       
Precip Type           snow         snow         snow     
Liquid Amt            0.00         0.07         0.06     
Snow Ratio(SLR)       15:1         15:1         13:1     
Snow Amt(in)          0            0-2          0-2      
Snow Level            1500         2000         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.