THIS AVALANCHE ADVISORY EXPIRED ON March 11, 2020 @ 6:24 am
Avalanche Advisory published on March 10, 2020 @ 6:24 am
Issued by Kevin Davis - Idaho Panhandle Avalanche Center

Selkirks/Cabinets

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Powder.  It's out there and deeper than I expected.  Surface conditions across the landscape are variable due to sun and warmer temperatures.  Due north still holds powder snow but also the surfacehoar layer.  It is well bonded now but still intact.  Use caution on steep, convex northerly terrain.  Springlike conditions are beginning to happen.

How to read the advisory

Selkirks/Cabinets

How to read the advisory

Powder.  It's out there and deeper than I expected.  Surface conditions across the landscape are variable due to sun and warmer temperatures.  Due north still holds powder snow but also the surfacehoar layer.  It is well bonded now but still intact.  Use caution on steep, convex northerly terrain.  Springlike conditions are beginning to happen.

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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    Very Likely
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    Unlikely
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I was up near Hidden Lake in the northern Selkirks yesterday doing snotel work and was surprised to find about 1 foot of cold, light powder at about 5,000 feet on the north side of Joe Peak.  This snow was very low density.  There was a shear at about 1 foot deep where the new snow had not yet bonded to the old surface.  Not a problem because of the low density but it had me thinking about where this layer might be warming up and getting heavier during the day if temps rise or if it gets direct sun.  It could just result in loose wet slides but could form a slab avalanche in the worst case.

Avalanche Problem 2: Persistent Slab
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That surfacehoar worked its way into every nook and cranny in our mountains.  It is still nicely intact but it doesn't shear until you really whack it.  It is getting unlikely that you will trigger this weak layer which is two feet deep in the northern Kirks but its good to keep in mind the type of terrain where it could happen, steep, convex northerly aspects.  If daytime, or anytime, warming begins to soften north aspects this layer could become easier to trigger.  Where there is surface hoar there is powder right now.  You'll find great powder sliding in the trees and this recent snowfall seemed to come with little wind.  It's very fluffy.

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Like I said, I was not expecting to find a foot of new, light powder on our trip into the Hidden Lake snotel.  It almost got deep enough to turn us around in our Mule with tracks.  We only made it to 5,000 feet at the snotel site so I imagine it could be even deeper up higher.  The snow should be best in the trees out of the sun but even snow in the open was not getting too effected by radiation.  The weather this week should preserve this cold snow on the north but we may begin to see some warming on southerly aspects, especially on sunny days.  Realize that light, new snow can destabilize quickly when the sun gets on it.  Look for shooting cracks under your skis or glide cracks opening up on steep slopes.

Weather and CURRENT CONDITIONS
weather summary 
Aside from a chance of mountain showers today and Wednesday, the
weather should be dry and mild. Expect a big weather change
Friday into the weekend with blustery winds, snow and much colder
temperatures. Expect dry but cold weather into early next week.
Weather observations from the Region
0600 temperature: 21 deg. F.
Max. temperature in the last 24 hours: 38 deg. F.
Average wind direction during the last 24 hours: W
Average wind speed during the last 24 hours: 10 mph
Maximum wind gust in the last 24 hours: 20 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 100 inches
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.