In Our Backyard

>I try not to be complacent about any of my backcountry skiing but it sobered me when I heard late yesterday that a group of our local skiers were involved in avalanche activity in the Girl’s Camp Bowl area off Pine Creek, between Swan Valley and Victor. Very fortunately, no one was buried or hurt but it reminds me that all skiable slopes must be treated with respect, even ones I think of as “close to home”…low elevation….the “go to spot” when other areas are too dangerous.

I headed to the site this morning with Rick to check out the avalanche to see what I could learn and to add to my understanding of snow dynamics and my own decision making.
The slope was skied late in the day and the temps were warm. We saw lots of rollers and sluffs on the way up but the night was cold and we left the parking area in the teens.
We dug 2 pits of our own, both about 6700-6800′, the same elevations as the avalanche and on similiar aspects. Our second pit was about 100′ west of the avalanche. Both pits showed relatively stable conditions (high 20s on the compression tests) and the layer that did shear was an older buried surface hoar about 2′ down , not the more recent buried layer from last weekend.

Looking at the avalanche events, we saw 2 slide areas, one that slid into a subtle drainage feature and was about 50-70′ wide with an 8-12″ crown; the other started east of the first and a bit lower in elevation, triggered by a traversing ski cut and it too was 50-70′ across with a 12-14″ crown. The sliding surface appears to have been the latest buried surface hoar layer and the snow from both slides merged to form a large debris field that filtered through a stand of trees before settling out in brush 200-300′ downslope.

http://www.youtube.com/get_player
This video shows our test pit about 100′ west of the slide and of the slide area itself

Debris fields from two naturally released slides west of the avalanche. You can see a narrow slab pull-out just right of the small tree upper center on the slope

upper edge of the debris field and below the bed surface of the first/westmost slide

likely trigger point for the first slide, upper center on a small rollover, you can also see the crown depth to the right

looking west towards the GC Bowl over the east/second slide with the west/ first slide in the gentle drainage behind Rick. Notice the crown depth above Rick and the smooth bed surface of the slide

 

looking at both slides

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4 responses to “In Our Backyard

  1. >Rick and Turbo you guys are awesome! These photos are great and really help you see the whole area, only thing is that just by looking at it you would never know that it went in four separate slides.In the third picture you can see the impact of where Mark Mckenna was skiing and took a digger triggering the first slide, low on the slope. Josh came in just below the small pine tree and Arlin and I came in just above the willows near that tree(2nd pic). Arlin was a bit west of us and as he stopped he triggered a decent size slide that quickly funneled into the depression and through the trees. After everything stopped Mark quickly made his way East to a lower angle slope and safe spot in the trees. Then Josh, snowboarding and trying to stay as high as possible, traversed to the east. As he went he triggered two separate slides. The first about 15×20 and the second about 60×20.Then sequentially from lowest on the hill up we all made our way eastward to a lower angle slope that is very wooded. We had dug a pit just off the ridge about 60' and found there that whore frost layer to be week, causing us to move further to the west in hopes it would be better. The danger over there was the rapid slope change, causing that layer to be week. Whats interesting to me is that when Turbo performed his test just 150' west of where we were, he couldn't get that layer to slide.All in all it was a good day with a lot learned. Just glad no one was injured.

  2. >Scary! I had not heard about this. Was the slide Saturday?A couple of us went up Stouts today following your skin track. We found highly variable spring like conditions. As we were preparing to ski at the summit, we triggered the biggest "whump" I've ever heard. Made my knees shake, and we took a pretty conservative line down to the bottom. It was still a great run.

  3. >Justin – thanks for the insight to the events of yesterday. I spoke with Ricardo and Turbo this afternoon and suggested that the reason for the significant differences in their test vrs your rapid succession of slides is most likely due to the warm 30+ degree temps from the late afternoon time frame you guys had yesterday compared to the cold 17 degree early morning temps of today when investigating the avalanche site. I may be wrong but this is the only reasonable difference i can come up with based on the info from you yesterday and what the boys gathered today. I think the low elevation, above freezing temps, recent snow covering a blanket of surface hoar, average slope angle of 35 to 38 degrees and the late afternoon hour (maximum stress on the snowpack due to sun and temps) are likely what conspired against you guys. We're just extremely glad everyone escaped unhurt!I am all ears if anyone has other suggestions about the possible reasons for the differences in data. Eric -Sweet. I sure love that side of the mountain. Amazing views of the South Fork Valley. We remotely triggered a cornice collapse just to the east of the summit upon our arrival. No warning. Needless to say it spooked us all as we watched the debris crash down the northest face and pull out a loose snow slide that ran for a few hundred feet. It was definately warm yesterday and made the snow heavy for us. I can only imagine what you guys had today! Got any photos??

  4. >Many of us have had reminders this weekend that snow and it's variable conditions are to be respected.I love the thrill of the snow covered hills but I also want to come home every night….I know each of you do too. Let's keep learning and respecting….

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