THIS AVALANCHE ADVISORY EXPIRED ON February 16, 2019 @ 6:04 am
Avalanche Advisory published on February 15, 2019 @ 6:04 am
Issued by Melissa Hendrickson - Idaho Panhandle Avalanche Center

St. Regis Basin/Silver Valley

bottom line

The snowpack is still adjusting to the heavy loading we had earlier in the week; add to that the new snow and high winds we got last night and we have a snowpack that is still working on stabilizing. It is still possible to trigger slides that are 1 to 3 ft in depth, especially in wind loaded areas.  With all the new snow out there settling some; riding and sliding is great in terrain that is under 30 degrees.  

How to read the advisory

St. Regis Basin/Silver Valley

How to read the advisory

The snowpack is still adjusting to the heavy loading we had earlier in the week; add to that the new snow and high winds we got last night and we have a snowpack that is still working on stabilizing. It is still possible to trigger slides that are 1 to 3 ft in depth, especially in wind loaded areas.  With all the new snow out there settling some; riding and sliding is great in terrain that is under 30 degrees.  

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.

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: Storm Slab
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We've had lots of storm snow over the last couple of days and it keeps on coming.  The snowpack does not like quick changes and the amount of loading we've received qualifies as a quick change. It will still be likely to trigger avalanches in steep terrain which can break 1 to 3 feet deep, propagate wide and have dangerous consequences.  Pay attention to your terrain as you are travelling, watch for slope angle changes and stay conservative.   The photo below is of a natural slide from yesterday in a storm slab showing the size of crowns possible in the backcountry right now. 

 

Avalanche Problem 2: Wind Slab
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Strong winds and lots of snow to move around are a recipe for large wind slabs.  Yesterday it was possible to trigger wind slabs that were several feet thick.  Give starting zones a wide berth and look for cross loading in the open trees as well.  Wind slabs will look like rounded pillows, chalky colored, and hollow sounding.  Pay attention in the flats if you have whumphing or shooting cracks, those are mother nature's watch out signs. Below is a photo from wind slabs and cornice build up that were easy to trigger yesterday.    

 

Avalanche Problem 3: Persistent Slab
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Our persistent slab rose looks a bit different this forecast than our last one.  With the storm systems that rolled through; heavier, denser snow landed on top of last week's light, fluffy, cold snow.  This is forming a hard slab over weaker layer in the snow in some areas.  This will take some time to stabilize.   There are also rounding facets in the snowpack associated with the crusts that were buried with the colder snow last week. These weren't reactive in pit tests, but the possibility of a storm slab avalanche stepping down and triggering these layers as well is a real threat.   This will produce a wider, deeper, and more destructive avalanche. Low angle terrain is the best cure for this problem.  If you hear whumphing, this is a red flag that this danger is lurking.    

recent observations

There were lots of reports yesterday and Wednesday of natural and human triggered avalanches, thank you everyone for getting observations to us. While we made it out of that high danger cycle, considerable conditions still exist.  Yesterday, as we were travelling to the FAA Ridge above Lookout Pass we were finding evidence that the storms have settled, but enough indicators of danger that still warrants safe travel choices.  Our snowpack this winter has been complicated and now just got a 2ft blanket to further bury those complications. Don't get powder fever and overlook all the dangers lurking under the new white coat.  Yesterdays video update here: https://youtu.be/xKSUwa7WNEA

Weather and CURRENT CONDITIONS
Two-Day Mountain Weather Forecast Produced in partnership with the Spokane NWS
For 2000 ft. to 4000 ft.
Friday Friday Night Saturday
Weather: Snow Showers Snow Showers Likely Snow Showers Likely
Temperatures: 29 deg. F. 22 deg. F. 28 deg. F.
Wind Direction: SW SW SW
Wind Speed: 9-15, G23 10-13 10
Expected snowfall: 2-4 in. 1 in. <1 in.
For 4000 ft. to 6000 ft.
Friday Friday Night Saturday
Weather: Snow Showers and Patchy Blowing Snow Snow Showers likely and patchy blowing snow Snow showers likely and patchy blowing snow
Temperatures: 25 deg. F. 22 deg. F. 23 deg. F.
Wind Direction: S SW SW
Wind Speed: 20-25, G34 18-21, G29 15-17, G26
Expected snowfall: 3-5 in. 1-3 in. 1 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.