Avalanche forecast

Silver Valley & Bitterroot Mountains

Idaho Panhandle Avalanche Center
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Avalanche danger

Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Mother Nature has decided that this week we will pretend that it is spring already!  That means as the day heats up, the surface of the snow is going to become sloppy and the potential for wet avalanches increases.  As those slopes start to bake and you start seeing pinwheels, it's time to move to the cooler side of the mountain or head down for the day.  Our deep buried persistent weak layer is still down there, less and less reactive, but if it is triggered, the consequences are going to be very high.    

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    Diurnal fluctuation.  During the day, when the sun is out, the surface of the snowpack melts and gets slushy and sloppy.  When this happens, the potential for wet, loose avalanches increases.  At night, the temperatures go back below freezing and the snowpack locks back up, bridging anything that is underneath it.   Time of day and aspect become critical to minimizing our avalanche risk.  Get in and out early, before the snow has time to soften up too much.  If you are seeing rollerballs, snow bombs dropping off trees and starting loose point slides. or you are sinking over your boot-tops into slushy snow, it's time to hit the north sides or call it a day.  

    (3/11/2021) Loose Wet Slide idicators of snow peeling away from rocks and creating rollerballs.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    3–4

    Believe me, I wish as much as you that we didn't still have to keep talking about this layer!  It's been down there for almost 2 months now!  The buried surface hoar from way back in late January is now buried between 80cm and 150cm deep across the entire forecast area.  We still easily found it in our pits yesterday, and at the lower elevations was still reacting in compression tests.  Triggering is getting more and more unlikely, but if it is triggered, the consequences are high. You may notice that the location has changed slightly. It's not that it's disappeared elsewhere, it is just the crust on those aspects are more stout and bridging.  On the high north aspects, there is only a slight sun crust, so you have more of a chance of punching through this upper layer.  Low probability of triggering right now, but we can't forget this layer; it will probably become a problem again as we progress through spring.  

    (3/11/2021) CT26 Q1 @ 90cm down on buried surface hoar.

Avalanche Discussion

Yesterday we travelled in the Burke area and saw lots of evidence of wet slides, including a large one that had run across the snowmobile trail and required a bit of trailbuilding to get through!  As the day got warmer, there were lots of pinwheels and tree bombs that were setting off small loose wet slides.  The weather was great, so we could see long distances, including the glide cracks on Tiger Peak.  As the temperatures increase, it's important to keep in mind the other warm/wet problems: glide cracks and cornices.  The warm temperatures increase the danger of these problems.  Give them a wide berth.  A larger cornice fall has the potential to step down and trigger a slide on the buried persistant weak layer. 

We searched as hard as we could to find some north facing powder: there is a little bit in the shaded areas up high.  But even there we found a thin melt-freeze crust from last week's unusually warm temperatures as soon as you had any open sunny pocket.  

Thank you everyone that participated in the observation contest.  Just because it is over, doesn't mean you have to stop submitting observations.  They have been much appreciated!

Also, the Doug Abromeit Youth Scholarship is still open.  Check out the details here.  

 

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