THIS AVALANCHE ADVISORY EXPIRED ON January 4, 2020 @ 5:29 am
Avalanche Advisory published on January 3, 2020 @ 5:29 am
Issued by Ben Bernall - Kootenai National Forest

Kootenai

bottom line

There is a alot of variance in the snowpack and some tricky weak layers across the area right now. Storm slabs resting on buried surface hoar will be the primary concern and may become more sensitve on Friday if the temperatures rise at mid-elevations. Stick to lower angle terrain and take the time to assess the snowpack before committing to steep slopes.

How to read the advisory

There is a alot of variance in the snowpack and some tricky weak layers across the area right now. Storm slabs resting on buried surface hoar will be the primary concern and may become more sensitve on Friday if the temperatures rise at mid-elevations. Stick to lower angle terrain and take the time to assess the snowpack before committing to steep slopes.

3. Considerable

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

3. Considerable

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

1. Low

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Below Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
    Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Storm Slab
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On New Years Eve we recieved widespread snow across the region at elevations above 5,000'. In the Purcell Range there is currently about 8-10" and in the Cabinets snotel sites recorded 12-15" during that period. Much of this dense new snow is resting on a bed of lighter snow and buried surface hoar. Use caution this weekend in steep terrain and take the time to dig a pit to see if this new snow is still reactive at your location. Steep areas with open timber will be likely trigger spots as they will be harboring this layer of buried surface hoar.

Avalanche Problem 2: Wind Slab
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Strong southwest winds and another fresh shot of light snow will create pockets of windslab on north and east aspects at upper elevations throught the weekend. Be on the lookout for a "pillowy" appearance in the snow and use caution just below ridgelines on these aspects.

Avalanche Problem 3: Persistent Slab
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I don't like to beat dead horses; but, I think this horse may still have a light and thready pulse. So, I am gonna keep swinging for a bit. 

Deep ice crust layer from November 19th sandwiched by layers of sugary snow. Most locations are showing it to be unreactive and not a concern; but, in isolated locations where the snow is thinner and the terrain is rocky and prone to weak spots. Triggering this weak layer could happen.This layer is very widespread across NW Montana and seems to have the same unpredictable nature. Just approach thin and rocky terrain  above 6,500' with a bit of skepticism for now. 

advisory discussion

There is a lot going on in the snowpack right now and a fairly high degree of variabilty across the area. The best plan of attack is to stick to lower angled terrain this weekend. Don't be fooled into the idea that trees are the safe spot as they are the areas that are most likely to be holding the weak layer of feathery surface hoar crystals 8-15" below the surface of the snowpack. If it's steeper than 30° it can slide. Another wildcard in the mix is the weather, that freezing line has been erratic this winter. If you see the surface of the snow pack producing "roller-balls" or just getting wet and sticky this is a sure sign that it will be getting weaker and more likely to avalanche. Stay off the steep stuff if you see this scenario develop at mid elevations today and Saturday.

Lastly, there was a recent avalanche incident in the Seeley Swan area involving 3 snowmobilers and resulted in two fatalities. Our deepest condolences go out to the family and friends of those involved.

 

 

 

Weather and CURRENT CONDITIONS
weather summary 
DISCUSSION:  

NORTHWEST MONTANA: Expect between a trace to 2 inches snow through
midday today, particularly along the Continental Divide near
Glacier Park. Ridgetop winds will remain brisk from the southwest,
gusting over 40 mph this afternoon. Temperatures today will warm 
around 5 degrees above Thursday readings. Many locations will
remain above freezing through tonight. A cold front Saturday
morning will bring colder air back over the terrain, with several
inches snow accumulation along and behind the front. Winds will
shift to westerly and gust over 50 mph causing white-out
conditions with the showers. A near carbon copy of the Saturday 
cold front will occur Sunday evening, but widespread 50+ mph winds
are less likely. Another round of light snow can be expected on 
the terrain. Drier and a warming trend present Monday through much
of next week.
Kootenai:

--------------------------- 5000-7000 FT ----------------------------
                      Today        Tonight      Sat      
Cloud Cover           90%          50%          100%     
Hi/Lo Temps           29 to 36     21 to 28     28 to 34 
Winds(mph)            SW 24G52     S 23G55      SW 37G68 
Precip Chc            80           40           90       
Precip Type           snow         snow         snow     
Liquid Amt            0.08         0.07         0.36     
Snow Ratio(SLR)       15:1         10:1         19:1     
Snow Amt(in)          1-2          0-1          5-12     

Snow Level            3500         3500         2000
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.