Monday, February 25, 2019

North Ogden Divide Avalanche AS SS D2 Windslab



         Kory here with Ogden Avalanche, with the thought of full disclosure, I am going to ramble at you for the next couple paragraphs.  Today I went for a small ride in a wind slab avalanche on the North Ogden Divide.  Earlier that day, I had triggered a couple of other small avalanches on test slopes at similar elevation but different aspect.  I knew that the probability was high to trigger an avalanche as I skied across the slope.  Please do not think that I am downplaying the event.

          I turned to my partner and said "lets see if we can get this to avalanche"  I started my ski cut across the slope with speed.  The slope fractured above me, which surprised me, since I thought I was at the break over.  I kept moving trying to ski off slab when I could not continue my forward progress.  I started going for a ride.  I looked around still on my feet trying to gain momentum to out ski the slide but I could not.  I tipped over uphill, skis down hill riding on top.  Not to worried.  I was able to stand back up and ski off the slab about mid path.
Red is Ski cut, Green is ride.

            I have written this many times before.  My infatuation with avalanches and triggering them has gotten me caught in a bad spot before.  I knew the slope would likely slide.  I knew the consequence was not as low as I would like it to be.  I wanted to test the slope anyways.  Why?  I am unsure.  I find avalanches very interesting and we can learn more about the snowpack by triggering them in safe situations.  So this is my dilemma, am I walking to close to the line?  Are you walking too close to the line?  Remember that risk tolerance is different for each person.  We all look at risk and reward differently.  My two cents would be to make conscious decisions and understand the consequence.  Do not go into these situations blindly.  

 Drew's article about Danger was excellent and you can find it on the UAC website blog (I am Dangerous). 


Here are some more photos.  Thanks again for listening to my rambles!




Deposition Pile

Sunday, February 24, 2019

2/17-2/24 Review, Powder Skiing and More Snow!




             What a week!  From wind, snow, and sun over presidents day to more powder and fluff through mid-week.  Last week was all time.  stable avalanche conditions, sunshine, calm winds, deep trail breaking and even deeper turns!  Late February is always good but this year was especially great.  We have a deep snowpack and stable conditions and a dry storm filled with cold air invection created the ultimate powder skiing week.   We did see some large (D2) Loose Dry Avalanches, and some Storm Slabs that settled out pretty quick.

BLOWER!
Very Deep Trail Breaking
Large Loose Dry Deposition Piles

              Now looking to the future.  I sit looking at the Ogden Mountains.  There are giant plumes, as prefrontal Southwest winds have returned to the Ogden Mountains.  This will create reactive wind slabs.  Winds are currently blowing 20-30mph out of the SW with gusts in the high 40's.  These should settle down mid-day Monday as the front pushes through.  We are looking to get 10-15 inches of snow and 2.5ish" of SWE throughout the week, with a possibility of more through the beginning of March.  This storm will once again bring dangerous avalanche conditions to the Northern Wasatch and Ogden Zone.

U of U Atmospheric Sciences Department
U of U Atmospheric Sciences

                The Snowpack is looking pretty good in the Ogden mountains with no "outlier" avalanches occurring this week.   The only problem is the snow surface on MOST East through Northwest aspect especially above 7500ft.  We received so much low density snow over the week that our snow surface has started to facet through.  This is due to high temperature gradients in the top layer of snow.  Cold clear nights, with cold windless days have created this weak layer.  Todays winds could help disturb this layer of Near Surface Facets (NSF), but only time will tell.  Be aware of touchy avalanches as it starts to snow.  If you choose to travel in protected avalanche terrain the next couple days, bring your a game.  This weak layer could become a persistent weak layer (PWL) over the coming week.


Friday, February 15, 2019

February 15 Snow Conditions.

        I am honestly not sure what to think about the current snowpack in isolated areas of the Ogden Zone.  I had notable pit results today with poor snowpack structure.  This worries me as we move forward into this storm.  With that said we already added a tremendous load to the snowpack without tons of notable natural avalanches on this buried weak layer.  I am not calling it a PWL yet because it has yet to produce many avalanches.

      Today I had ECTP SC 22 and 25 on a layer just above the Tom Brady storm rain crust.  This surprised me.  This layer formed last Thursday (Feb 7th) at the end of the Tom Brady storm when we received a light dusting of low density snow that did not get settled by wind or sun.  This layer was than preserved later in the week.  I do not know going forward how reactive this layer will be.  This layers reactivity did surprise me today though.

      Large avalanches in Willard Headwall could have failed on the same layer or just large well connected windslab.  Unsure due to poor visibility.
Bill Brandt Photo

Bill Brandt Photo


     

       Second part of the story is the extent of Hard D2/3 Windslab avalanches at Snowbasin today with explosives.  These avalanches seemed quite touchy and definitely could have been triggered by a human.  Some of these avalanches had crowns up to 4ft deep.  The other amazing part is how well connected some of these avalanches were.  Some connecting through rock bands similar to how a Persistent Slab avalanche would act.  
     

       The Third part of the story.   Impressive Wet/Wind Slab avalanches observed today.  I was surprised at how far these ran they were also quite destructive as imagined.  Also some D2+ Wet Loose avalanches.  This cycle is over now!