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Avalanche Debate
Posted: 12 September 2008 04:44 AM  
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Well, calling it a debate may go a bit far, but at Teton AT they posted a video of an Avalanche in Hatcher’s Pass Alaska.  They are skiing with dogs, and the slide starts when a kid hops off a small rock, falls, and releases a slab.  The post on Teton AT goes on to talk about backcountry safety saying

“ Dogs in avy terrain?  NO!!!
♦ Are you truly in a safe zone?
♦ Is it smart to huck in the BC?  NO!!!”

which seems to have gotten some people angry in the comments.  I think it’s more a question of ability and judgement (as the blog’s author states as well) and don’t have any real problem with the rock dropping in general but think it’s more a function of judgement in general.  The particular area is known for extremely large surface hoar, similar slides are common.  I’ve personally had a horrible experience where a small rock drop triggered a slide, but still insist it was a judgement issue (horrible day to be in the area) then a particular rock dropping or large group issue.  Although they both contributed.

I would be interested to hear what people on this site thought of the issue, general thoughts on the necessity of conservative skiing in the back country would be excellent.

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Posted: 15 September 2008 09:44 PM   [ # 1 ]  
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Good movie. We don’t get many dogs in the French backcountry. Still most of the pooches are toy poodles so wouldn’t cope! There are a few strays in the mountains though which tend to follow you around.

One guy I know had his dogs take a nasty tumble crossing an ice covered slope, he had ski crampons. That doesn’t seem reasonable and the dogs were badly shaken. I’m not sure I have much of an opinion beyond that really - I can see that a distressed dog would hinder a rescue operation, particuarly where other dogs are involved.

Hucking - yeah we see it all the time in the movies, especially off cornices… which seems like Russian roulette given the landing zone will be wind loaded. In this case they were hucking off a rock. Being wise after the event rocks have two effects. They channel the wind and snow and can cause loading and they conduct heat into the snowpack giving a temperature gradient and leading to the formation of depth hoar (TG Snow), a weak layer. The snowpack may be thinner below the rocks. The rocks also cause stress in the snowpack and can be a trigger area. If the skier hadn’t fallen he may have gotten away with it, as his fall would have put more load on the slab that he triggered. I think it was a risky place to huck myself but I wouldn’t say no hucking, 100% I guess on ski films a guide does a risk assessment, but it is still dangerous. Plus those skiers are paid to risk their skins.

At the start of the video you can see the slope is on the lee side as there is a small lip. The big cliff to the left doesn’t give me much confidence. The other skiers are also quite heavy with their skiing. The danger of fat skis getting poorer skiers into trouble. I think I would have waited more off to one side out of the runout zone.

Of course all of that is not always practical and we sometimes get caught up in the euphoria of the moment.

 
 
Posted: 16 September 2008 02:45 AM   [ # 2 ]  
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I also watched that short film.  My first instinct is, most of the skiers previous to the one that triggered the slide, skied the left side of the ridge out of danger.  I dont necessarily think the huck off the rock was a bad judgement I believe his line that he skied once he landed was a poor. Although a avalanche happen and might of have been prevented I believe these guys got caught up in the moment.

 
 
Posted: 07 October 2008 09:55 PM   [ # 3 ]  
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This looks like a case of propogation as each loading progressively weakens the interface between layers until it fails.  Shit happens, lucky dog !!

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