THIS AVALANCHE ADVISORY EXPIRED ON February 16, 2019 @ 6:22 am
Avalanche Advisory published on February 15, 2019 @ 6:22 am
Issued by Kevin Davis - Idaho Panhandle Avalanche Center

Selkirks/Cabinets

bottom line

Big week for storm snow riders!  Shifting winds this week have loaded multiple aspects and storm slabs are touchy.  Steep, windloaded areas below ridges and cornices will be the most hazardous areas today and this weekend.  Don't approach cornices from above or below since cornices have built up to the breaking point this week.

How to read the advisory

Selkirks/Cabinets

How to read the advisory

Big week for storm snow riders!  Shifting winds this week have loaded multiple aspects and storm slabs are touchy.  Steep, windloaded areas below ridges and cornices will be the most hazardous areas today and this weekend.  Don't approach cornices from above or below since cornices have built up to the breaking point this week.

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: Wind Slab
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Wind sculpted some large cornices this week as well as moved alot of snow.  North, east, and west winds, and variations in between battled all week and created a hodge podge of windloaded areas.  Typical windloading patterns are not the norm right now.  Our experience in the Selkirks near Mount Casey yesterday was windloading was not obvious and we expected more touchy slabs on the SW and not the normal NE aspects where we normally see it.  Although highly variable, I expect you will be able to find some touchy windslabs on any steep aspect today.

Avalanche Problem 2: Storm Slab
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Snotel sites are not accurately reading 24 hour accumulations.  Water equivalent accumulations show 2" and 1.6" for Schweitzer and Hidden Lake, respectively which could be 16 to 20 inches of snow!  Schweitzer is reporting 8" on the snow stake.  Bear Mountain, the snow factory, only shows .5 SWE in 24 hours which has me scratching my head.  What you need to know about last nights snowfall is it is heavier due to rising temperatures.  That's why the snotel snowdepth decreased overnight.  That means heavy over light which is inherently unstable.  We saw this in our snowpit yesterday so we potentially have a multilayered cake of dense/less dense layers of snow.  We did not see any fracturing or propagation of weak layers in the pit nor shooting cracks or whumphing during our travels.  We hit north and east aspects from 5,000 to 6,000 feet with sled and skis pretty hard too.  Check these varying density storm slabs above the ice crust often in your travels since they are variable too.  Big, steep, open and convex slopes are the areas I would avoid today.

recent observations
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This will be one of the big weeks to remember this year.  Some avalanche activity to note; avalanches on Lookout Pass close the highway on Wednesday.  Some drivers were stranded.  A snowmobiler up Burke Canyon was partially buried when a roadcut slid.  They were able to dig out and no one was hurt.  No reports of avalanches in the Selkirk/Cabinet region but high winds and 2-3 feet of new snow this week should have your attention.  The pack is settling and the snow from last night and warmer temps seems to be adding enough weight to settle the pack even quicker.  Be suspect that the settlement and lack of red flag warnings, like shooting cracks, avalanches, and whumphing is enough to create safe sliding everywhere.  We did have some great riding and sliding yesterday.  Just watch your exposure to hazards and have your rescue game on in case something does happen.  The weekend weather will continue a gradual settlement of the pack but could create a denser slab on top that could become a problem.  We'll just have to wait and see.

Weather and CURRENT CONDITIONS
weather summary

Sounds like another great day in the mountains with a couple more inches of snow expected in the morning today, winds shifting to the SW at about 10-15mph, and temperatures in the mid 20s.  

Weather observations from the Region
0600 temperature: 23 deg. F.
Max. temperature in the last 24 hours: 24 deg. F.
Average wind direction during the last 24 hours: E
Average wind speed during the last 24 hours: 15 mph
Maximum wind gust in the last 24 hours: 20 mph
New snowfall in the last 24 hours: 8 inches
Total snow depth: 108 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 likely, mainly before 7am, then snow showers likely after 10am. Cloudy. Chance of precipitation is 70%. Snow showers likely, mainly before 10pm. Cloudy. Chance of precipitation is 60%. A 40 percent chance of snow showers, mainly before 4pm. Cloudy.
Temperatures: 34 deg. F. 29 deg. F. 34 deg. F.
Wind Direction: East SW SW
Wind Speed: 6mph 5mph 3-6mph
Expected snowfall: 1-2 in. 1-2 in. 1-2 in.
For 4000 ft. to 6000 ft.
Friday Friday Night Saturday
Weather: Snow likely before 10am, then snow showers, mainly after 10am. Patchy blowing snow before 10am. Chance of precipitation is 80%. Snow showers likely, mainly before 10pm. Patchy blowing snow before 10pm. Cloudy. Chance of precipitation is 60%. A 50 percent chance of snow showers. Cloudy.
Temperatures: 26 deg. F. 22 deg. F. 27 deg. F.
Wind Direction: SW SW SW
Wind Speed: 13-17mph 14-16mph 13-16
Expected snowfall: 2-4 in. 2-4 in. 2-4 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.

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