Home > Trip Reports > December 17,15 Avalanche: Big Trees and Spin Drift

December 17,15 Avalanche: Big Trees and Spin Drift

12/17/15
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Posted by Good morning on 12/20/15 4:33am
Are you a pussy or are you an idiot? We usually take a moment to reflect on this question and the present snow conditions before we take any questionable line. Today we didn't think twice. We should have.

Snow was falling hard and swirling about. On the open slopes above source lake it felt stable enough; loose unconsolidated delicious powder on a dense layer that was well adhered to the bottom crust. NWAC described the day as considerable but rising. What we failed to consider was all that spin drift piling up in the concave region below the cliffs. We were slightly off our intended line, to skier's right of Big Trees below Pineapple Pass. There was plenty of tree anchoring. We were above two usually skiable cliff bands. I dropped the first one and cut right for maybe a turn or two. Then the ground gave way-that ugly feeling...

I think I was still upright and kind of skiing when a wave of snow hit me on the side of the face. Now I was full in. I tried to find bottom to arrest. No bottom.  I tried to keep my limbs about me. I tried to stay upright, protect my head, swim, I can remember bouncing off things. I tried to keep my wits about me. I can remember slowing enough to steer towards some smaller trees. I hit one and grabbed hold. I remember fighting to keep my mouth clear and climb up as the snow washed over me. Another wave of snow hit me from behind. I remember taking as big of a breath as I could.

Then it was over. For a long moment my world was white and I hugged that tree.

My partner could see that as soon as I got below the cliff a 1.5 foot fracture propagated to the side and the whole slope failed. He saw me on top of the snow and struggling for a ways then I disappeared from his sight as I went over the second cliff band. He started descending the slide path. He went to take one turn around a small tree on a low angled section just off the slide surface and into undisturbed snow. As soon as he got on the soft snow it triggered right up to the cliff face, maybe 25 feet. That slid onto him and carried him slowly across the low angle section into some small trees, burying him to the waist and spraining his knee in the process. Had he been carried around the trees he might have followed my much longer and rougher path.

The snow was soft and I was able to push my way to the surface. I took a long breath, several breaths. Body check: ok enough. I was out of my foxhole and calling out. I had one ski, no hat or goggles, but both poles. I never ski with the straps on, but they helped me defend against some of the thing I bounced off. As my partner was digging himself out and trying to assess the damage to his knee we made visual contact. He waved. We were damn happy to see each other. From there it was a matter looking for gear and limping out. He skied one leg. I skied one ski. We were both happy nothing worse happened.

So today we were indeed idiots. Yes, we knew better, most people who get swept do. Thinking it though, I must have undercut all that spin drift piled up at the cliff base. It hit me like a breaking wave. I never got to see the fracture crown. It was over 200 yds and a cliff band above me. Fortunately, I think, I got flushed down a sideways runnel through the cliff. The lessons seemed to be a) we developed an assessment on the slopes we climbed that we unthinkingly carried over to the cliff bands- a totally different terrain setup. B) if you€™re above when it slides ski only the slide path. Venturing just a few feet off that surface, even on a low angle section, triggered a second slide that could have had dire consequences for both skiers. As it was the pole he lost ended up just 20 feet below where I stopped. We found my hat another 60 feet down from that. The slide ran for several hundred more feet.

My ski and goggles will probably melt out in the spring. If you happen to find a Coomback 189cm with older Dynafit STs and an iridium lens goggle, give me a call. I know the probability is low, but if you're up there, or anywhere, even if NWAC only says "CONSIDERABLE", do consider our little question. Consider all the variables.

See you in the bar.
Dave from W Seattle 769-7448
So good to be alive.

Thanks for sharing your experience.  These kinds of posts, humbling as they may be, serve a very real and valuable purpose in sharpening our collective wisdom and restraint.  Glad you both got out okay, under your own power, no less.

Thank you for sharing your experience. Very glad to hear you both walked away from it.

Thanks for the post. Good for the rest of us to keep this in mind when we make our own decisions whether to be pussy, idiot, aggressive, bold or what have you.

Glad no one was seriously injured.

"even if NWAC only says "CONSIDERABLE"

From the North American Public Avalanche Danger Scale:
Considerable
Likelyhood of avalanches: Natural avalanches possible, human triggered avalanches likely

Huge kudos and thanks for sharing this Dave as you and your partner will go through a series of 'would have and should haves' for quite some time.  A process I still go through nearly on a daily basis following the avi that swept me and 2 friends out of our group of 5 on April 6th, 2011... for me resulting in life changing injuries...The fact that you had the courage to share this is a great sign that you'll add this experience to your thought process when assessing terrain, conditions and commitment level to your passion for playing in the mountains. 
You've probably already seen this, but a reminder that it's always o.k. to pull the plug on the 'objective' and choose a different line...there is no such thing as a 'pussy' when it comes to pursuing adventure

https://vimeo.com/56783758


Thanks for the post, I imagine there are all kind of emotions swirling around, glad you are still around to tell the story, and really glad you told it here, thanks again.

author=unclepen link=topic=35132.msg144146#msg144146 date=1450674337]
Glad no one was seriously injured.

"even if NWAC only says "CONSIDERABLE"

From the North American Public Avalanche Danger Scale:
Considerable
Likelyhood of avalanches: Natural avalanches possible, human triggered avalanches likely
I have a feeling that may have been facetious.

Dave - that is an awesome read. Thanks for sharing your story and the wisdom gained.

In the late 90's we lost a lot of very talented people in paddling. Prior to that, when scouting a rapid, if you decided to walk the response was, "Are you a pussy?" Now the response is universally, "Good call" - except maybe for paddlers who are in year five and haven't been trounced yet.

Maybe skiing isn't at that place yet. We need to be all need to be supportive of others decisions to not ski a particular slope, even if that person is us and we are listening to our inner voice. It is prudent to give up 1 to get 100 more.

We all learn a bit when someone writes a good trip report like this, thanks Dave.

Yes, we do live and learn. And there is no shame in playing the pussy card. Tonight is winter Solstice. For over 20 years we have skied in to Source Lake for a party to celebrate the longest night and the coming of winter. Tonight we again made the call to hold the party close in.  This decision isn't based on my freak out in the aftermath of Thursday, though I've been pretty entertained (and not always in a good way) by the range of emotions following such an accident. It's from an honest assessment of the risks and benefits from our current conditions. We've made this decisions several times over the years. Tonight we make it again.

I've thoughtfully read and greatly appreciate your replies. Thank you especially to all who've been there too. There's a certain understanding there. There is always some risk. Life, even if we just sit and watch it all on TV is fragile and full of risks. We measure the risks as best we can. We make the call. Sometimes we forget, we get too comfortable with the familiar, or we fail to consider a factor or two. We do our best most of the time. And we make mistakes. If we are lucky enough we get to tell others about it ourselves.

A good friend of mine used to say," no one is worthless. You can at least be a bad example." I'm happy to be able to share my foolishness.

Dave

Thanks much for the report.  I've been in that area before and fooled myself that it was safe because of tree anchoring.  Now I know better, and I hope I'll remember the lesson.

Thanks for sharing your experience, it can happen to anyone. It sounded pretty scary, I'm glad you came out OK.

I don't know if it played into what happened at all (it doesn't seem to have) but the comment about tree anchoring struck me. With recent snowfall I try not to think of trees as anchoring the snow, instead considering them as wind sheltered areas where there is less likely to be slab formation. I don't expect trees to anchor soft snow if a slide is triggered above, below, or amongst them.

Curious to hear any other thoughts, as it seems like fairly common thinking to assume as a rule that a treed area will provide anchoring.

My teaching has been that trees are only a safe area if they provide full overhead canopy. Meaning no surface hoar, little wind effect, and the healing properties of getting tree bombed every so often. Anything less is not truly safe. In fact in areas other then the cascades sparse trees on the edge of the slope can actually be a good place to trigger deep failures due to faceting around the tree stump. Often you can test the theory of "does this slope slide" by checking the branches on nearby trees, are they completely missing at a certain height above ground, are all the uphill branches gone, and is the tree of a similar size to what would be expected at that elevation.

Thank you for manning up(or manning down?) and sharing your close call with the rest of us.
Glad you're both alive to tell about it and I hope your partner heals quickly.

Thank you for the report. Can anyone take the attached photo, or create a new one, and mark the slope that slid. Perhaps someone with PhotoShop.

There are quite a few slopes that have slid in that area but it might help others that have not been in the Source Lake area.

Thanks

author=bc_skier link=topic=35132.msg144214#msg144214 date=1450797537]
Can anyone take the attached photo, or create a new one, and mark the slope that slid. Perhaps someone with PhotoShop.



Big Trees is a specific run.

Indeed.  Thank you! For sharing this in such a raw and honest fashion.  It is important for all of us.

Realizing that I myself have made bad decisions I offer a couple of thoughts only in the spirit of being a part of a community that I love.

1. Tree Anchors.  I think this is a bit of a myth.  Plenty of slides propagate in and through forested areas.  As someone else already mentioned, trees can actually be points of weakness in the snow pack.  At the same time we think of tree skiing as safer. But I agree it is not due to anchoring as much as being more sheltered.  Low angled trees is the ticket ... and what is ABOVE those trees makes a difference.

2. "Considerable" avalanche danger.  All of us have different risk tolerances.  But sometimes we are all blinded to the amount of risk we are taking.  My personal observation is that many backcountry skiers forget that "considerable" means that human triggered slides are likely.  In my mind that means that I myself and the final ingredient in the snowpack to basically guarantee avalanche activity.  And it is usually "large" in scope stepping down into layers and propagating wide.  With this in mind I have made it my own personal rule to be extremely selective with terrain IF I go out on a considerable day.  That means I choose terrain that has an extremely low probability of sliding AND that if it does slide, because anything skiable can slide, the consequences will be low and manageable.  For me choosing terrain means two things: 1. likelihood of sliding and 2. consequences if it slides.    Trees can break femurs and crack skulls in an avalanche.

Again, I am not trying to be critical.  Just sharing and humbly acknowledging my own myriad of mistakes.  I have learned to take "considerable" as "high" because introducing myself into the equation changes everything.  

Glad you came out OK. Appreciate you sharing your story, this has served as a wake up call/reminder to me and many others.

author=Roger Strong link=topic=35132.msg144154#msg144154 date=1450710596]
Huge kudos and thanks for sharing this Dave as you and your partner will go through a series of 'would have and should haves' for quite some time.  A process I still go through nearly on a daily basis following the avi that swept me and 2 friends out of our group of 5 on April 6th, 2011... for me resulting in life changing injuries...The fact that you had the courage to share this is a great sign that you'll add this experience to your thought process when assessing terrain, conditions and commitment level to your passion for playing in the mountains. 
You've probably already seen this, but a reminder that it's always o.k. to pull the plug on the 'objective' and choose a different line...there is no such thing as a 'pussy' when it comes to pursuing adventure

https://vimeo.com/56783758



never got to thank you for leading me and BradG @slot n slut some time back.
hope to catch you on the uphill of your second lap someday:-)
bobby


author=Good morning link=topic=35132.msg144101#msg144101 date=1450643634]
Are you a pussy or are you an idiot? We usually take a moment to reflect on this question and the present snow conditions before we take any questionable line. Today we didn't think twice. We should have.

Snow was falling hard and swirling about. On the open slopes above source lake it felt stable enough; loose unconsolidated delicious powder on a dense layer that was well adhered to the bottom crust. NWAC described the day as considerable but rising. What we failed to consider was all that spin drift piling up in the concave region below the cliffs. We were slightly off our intended line, to skier's right of Big Trees below Pineapple Pass. There was plenty of tree anchoring. We were above two usually skiable cliff bands. I dropped the first one and cut right for maybe a turn or two. Then the ground gave way-that ugly feeling...

I think I was still upright and kind of skiing when a wave of snow hit me on the side of the face. Now I was full in. I tried to find bottom to arrest. No bottom.  I tried to keep my limbs about me. I tried to stay upright, protect my head, swim, I can remember bouncing off things. I tried to keep my wits about me. I can remember slowing enough to steer towards some smaller trees. I hit one and grabbed hold. I remember fighting to keep my mouth clear and climb up as the snow washed over me. Another wave of snow hit me from behind. I remember taking as big of a breath as I could.

Then it was over. For a long moment my world was white and I hugged that tree.

My partner could see that as soon as I got below the cliff a 1.5 foot fracture propagated to the side and the whole slope failed. He saw me on top of the snow and struggling for a ways then I disappeared from his sight as I went over the second cliff band. He started descending the slide path. He went to take one turn around a small tree on a low angled section just off the slide surface and into undisturbed snow. As soon as he got on the soft snow it triggered right up to the cliff face, maybe 25 feet. That slid onto him and carried him slowly across the low angle section into some small trees, burying him to the waist and spraining his knee in the process. Had he been carried around the trees he might have followed my much longer and rougher path.

The snow was soft and I was able to push my way to the surface. I took a long breath, several breaths. Body check: ok enough. I was out of my foxhole and calling out. I had one ski, no hat or goggles, but both poles. I never ski with the straps on, but they helped me defend against some of the thing I bounced off. As my partner was digging himself out and trying to assess the damage to his knee we made visual contact. He waved. We were damn happy to see each other. From there it was a matter looking for gear and limping out. He skied one leg. I skied one ski. We were both happy nothing worse happened.

So today we were indeed idiots. Yes, we knew better, most people who get swept do. Thinking it though, I must have undercut all that spin drift piled up at the cliff base. It hit me like a breaking wave. I never got to see the fracture crown. It was over 200 yds and a cliff band above me. Fortunately, I think, I got flushed down a sideways runnel through the cliff. The lessons seemed to be a) we developed an assessment on the slopes we climbed that we unthinkingly carried over to the cliff bands- a totally different terrain setup. B) if you’re above when it slides ski only the slide path. Venturing just a few feet off that surface, even on a low angle section, triggered a second slide that could have had dire consequences for both skiers. As it was the pole he lost ended up just 20 feet below where I stopped. We found my hat another 60 feet down from that. The slide ran for several hundred more feet.

My ski and goggles will probably melt out in the spring. If you happen to find a Coomback 189cm with older Dynafit STs and an iridium lens goggle, give me a call. I know the probability is low, but if you're up there, or anywhere, even if NWAC only says "CONSIDERABLE", do consider our little question. Consider all the variables.

See you in the bar.
Dave from W Seattle 769-7448

the alpental bc is scary, glad your here to post after the ride.

author=danpeck link=topic=35132.msg144228#msg144228 date=1450808324]

2. "Considerable" avalanche danger.  All of us have different risk tolerances.  But sometimes we are all blinded to the amount of risk we are taking.  My personal observation is that many backcountry skiers forget that "considerable" means that human triggered slides are likely.  


Also slides very likely given certain terrain features such as Dave experienced.

Must remember that the NWAC forecast is generic for that area--an overall "average" danger assessment--and that specific features and aspects can easily be a grade or even two grades more dangerous than the NWAC forecast.

Later in the season many of those cliff bands in there disappear. It's a moderately steep gladed area. Lots of room for things to move around and lots of propagation points for slides.

I wonder if they were actually going down big trees and not more on the no-fog side of things.





Hi Dave - My partner and I saw you and yours shortly after you had regrouped and started to head out. Thanks for sharing the details of your experience here for everyone to learn from.

Did you happen to dig a pit while you were out? My partner and I used the day as our skills refresher so we dug a pit on a Southern aspect and practiced burial search and rescue in some very low angle terrain. We noticed a repeatable and easy (between 5-10 hand hits) Sudden Planar shear failure at about 22cm depth in our columns and a moderate (3-5 elbow hits) and more Resistant Planar shear failure at about 85cm depth. The conditions, as you discovered, were certainly unstable out there.

The top layer that was sliding more easily was definitely the storm slab and it was very light and cold snow. I wonder if the temperature and weight of the snow helped allow you and your partner to dig yourselves out?

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