Home > Trip Reports > Oct 27 Crystal Southback pow

Oct 27 Crystal Southback pow

10/15/10
WA Cascades West Slopes South (Mt Rainier)
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Posted by Scotsman on 10/27/10 9:52am
It was good.
PNWbrit, ChesterT,  FriendlyMark and I.
Views of Rainier were superb . I hope those that went to Paradise were rewarded with a great day.
Silver Basin skied good but wind was definitely causing it to slab.
Shaded areas skied like velvet.
Good coverage but you had to know where the talus fields were.
Think Rusty Knees and Teleskichica were up there but our paths didn't intersect.
My husky Chugach got very tired.

Picture courtesy of PNWBrit.

Edit to add.:On an equipment note. I fell on one of my runs and lost a ski that was attached using the B&D ski leash( it was attached to the ski with the breakaway zip tie protected by plastic tubing that B&D supplies and recommends). Breakaway link broke and ski was loose. Found it after 10 mins of digging but I was surprised it broke in a fall. Breakaway link needs to be strengthened if they are going to be any use as a ski retention leash.
Nice! Looks velvety.

Did it warm up?  Considering calling in sick on Friday and debating between Crystal or Chinook if it reopens. 


Wind was howling up Silver Basin causing snow to become more cohesive with every run. Ski track was filled by the time we started back up. Saw some crack propagation starting later in the day. Not enough snow to be really worried and vegetation anchoring still in affect but still good to be cautious.
Some natural sloughs in JBAS and 3way peak area on steeper aprons below cliffs.
24" snow on Silver Basin slopes as I dug to find my ski.

No real sun affect in SB while we were there but I heard from a skier at base who went to Green Valley that it was sun affected there.
Shaded areas remained velvety as long as we were there.
Lower hill snow melting fast.
Weather forecast could bring rain to lower base on Thurs.
I was told heli is booked for  Fri and Sat for Gondola tower erection= Personally worried that they will get it done.
Friday depends on freezing levels as to how good it could be. It was cold today.

author=Kyle Miller link=topic=17741.msg74877#msg74877 date=1288228835]
:'(


HAHAHA ;D
How was work at my office today Kyle? It's terrible when your boss goes skiing and you have to work. ;)
With the amount of riding you're going to get this winter, you're getting no sympathy from me! ;D

Yes... we were. Took a "first timer" out today and had a great time. I had to reset the clock after ankle breakage... so this is another full year of TAY for me and 4 for Mr. Knees!! Forgot my camera, but thankfully didn't forget how to ski powder. :)

author=Scotsman link=topic=17741.msg74874#msg74874 date=1288227177]

Edit to add.:On an equipment note. I fell on one of my runs and lost a ski that was attached using the B&D ski leash( it was attached to the ski with the breakaway zip tie protected by plastic tubing that B&D supplies and recommends). Breakaway link broke and ski was loose. Found it after 10 mins of digging but I was surprised it broke in a fall. Breakaway link needs to be strengthened if they are going to be any use as a ski retention leash.

Scotty,  I also use the B&D leash but I have not had a release to test the reliability of the plastic tubing covering the zip tie.  Could you post or send me a PM with your solution.

Nice call on Silver Basin versus the longer drive and gate issue at Paradise.

Thanks

Zap

Gotta love it!  Early season powder is something to savor - nice work!

We only had time for one lap in Silver Basin - the snow was deep and smooth.  Turns were great, falls were a lot of work getting back up  8)  We skied all the way down to the lodge - got a couple good core shots  :(.   The ole Reverends are pretty thrashed, finally.  Time for new skis!

author=Zap link=topic=17741.msg74892#msg74892 date=1288235613]
Scotty,  I also use the B&D leash but I have not had a release to test the reliability of the plastic tubing covering the zip tie.  Could you post or send me a PM with your solution.
Zap


Will do although I'm not sure there is a solution. Thinking about it last night I realized that in that fall I went over the handlebars and fell ahead of the ski , leaving it buried deep in the pow. For the breakway to have resisted that force it would have had to be strong enough to resist the force of a 200 lb guy travelling at 25 mph pulling directly on the leash. If it could withstand those forces it might not breakaway in an avy which is a MUST.

author=Zap link=topic=17741.msg74892#msg74892 date=1288235613]
Scotty,  I also use the B&D leash but I have not had a release to test the reliability of the plastic tubing covering the zip tie.  Could you post or send me a PM with your solution.
Zap

author=Scotsman link=topic=17741.msg74908#msg74908 date=1288281870]
Will do although I'm not sure there is a solution. Thinking about it last night I realized that in that fall I went over the handlebars and fell ahead of the ski , leaving it buried deep in the pow. For the breakway to have resisted that force it would have had to be strong enough to resist the force of a 200 lb guy travelling at 25 mph pulling directly on the leash. If it could withstand those forces it might not breakaway in an avy which is a MUST.


Were I in your shoes (boots?) I’d be going back to the ski brakes, guys ;)
They’re really not that much heavier that those 6 foot leashes you’re now lugging around and, like the bindings, they work pretty good when you understand their idiosyncrasies and take care of them.



author=ron j link=topic=17741.msg74916#msg74916 date=1288286843]
Were I in your shoes (boots?) I’d be going back to the ski brakes, guys ;)
They’re really not that much heavier that those 6 foot leashes you’re now lugging around and, like the bindings, they work pretty good when you understand their idiosyncrasies and take care of them.


mmmh. Food for thought. If I go back to brakes will you give me some Jedi lessons on brake care?

http://www.youtube.com/watch?v=aiG-aWihqds&feature=related

Edit to add: Problem is Dynafit brakes for a 125mm wide ski???? Superfat has it's issues when it comes to dynafit brakes.

author=Scotsman link=topic=17741.msg74919#msg74919 date=1288287904]
mmmh. Food for thought. If I go back to brakes will you give me some Jedi lessons on brake care?
http://www.youtube.com/watch?v=aiG-aWihqds&feature=related

I will.
You have the word of a Jedi Master.
It will be good to deliver you back from the darkside.


author=Scotsman link=topic=17741.msg74919#msg74919 date=1288287904">
Edit to add: Problem is Dynafit brakes for a 125mm wide ski???? Superfat has it's issues when it comes to dynafit brakes.


The challenges make you stronger young skywalker:
DYNAFIT TLT WIDE BRAKE 130MM



author=ron j link=topic=17741.msg74921#msg74921 date=1288288948">
The challenges make you stronger young skywalker:
DYNAFIT TLT WIDE BRAKE 130MM



Do they fit STS?

author=ron j link=topic=17741.msg74920#msg74920 date=1288288491]

It will be good to deliver you back from the darkside.


sorry, staying in the darkside= much more fun and since I'm an aetheist...  ultimate consequences of bad behaviour are irrelevant. ;)

author=Scotsman link=topic=17741.msg74922#msg74922 date=1288289245">
Do they fit STS?

They fit the Vertical FT 12 and Vertical ST bindings.


author=Scotsman link=topic=17741.msg74908#msg74908 date=1288281870]
Will do although I'm not sure there is a solution. Thinking about it last night I realized that in that fall I went over the handlebars and fell ahead of the ski , leaving it buried deep in the pow. For the breakway to have resisted that force it would have had to be strong enough to resist the force of a 200 lb guy travelling at 25 mph pulling directly on the leash. If it could withstand those forces it might not breakaway in an avy which is a MUST.


Would a ski brake help in that situation?  I've seen plenty a ski, such as my own, go missing on deep days in that sort of crash.  I sometimes wore powder cords last season, but those were a pain in the ass in their own way.  I suppose crashing less is one solution.  ;D

author=andyrew link=topic=17741.msg74925#msg74925 date=1288293409]
Would a ski brake help in that situation?  I've seen plenty a ski, such as my own, go missing on deep days in that sort of crash.  I sometimes wore powder cords last season, but those were a pain in the ass in their own way.  I suppose crashing less is one solution.  ;D

Good clarification, Andrew.
The ski brake suggestion was targeting Scotty's lack of confidence that the leash's fusible link would properly serve to hold on to the ski in a fall where you didn't want to lose it yet break so as to not keep the ski near you so if you happen to take "the Ride". Not may relish the idea of riding (tumbling) down the mountain with a 6' Cuisinart blade.  Obviously with brakes only, the detached ski is most likely gone (and possibly lost).
So you are right, if you want the skis to be easier to find once you stop tumbling, powder cords (or straps without fusible links) are the superior tool.


author=andyrew link=topic=17741.msg74925#msg74925 date=1288293409]  I suppose crashing less is one solution.  ;D

Well that ain't going to happen anytime soon!

author=ron j link=topic=17741.msg74930#msg74930 date=1288294945]
Good clarification, Andrew.
The ski brake suggestion was targeting Scotty's lack of confidence that the leash's fusible link would properly serve to hold on to the ski in a fall where you didn't want to lose it yet break so as to not keep the ski near you so if you happen to take "the Ride".

mmmmh. Why B&D ski leashes?
1) Brakes= I don't like dynafit brakes especially in deep snow. One of the people touring with me yesterday had brakes and they were definitely adding to his fiddle factor, getting clumped up and adding to his transition time.. significantly.. and when there's fresh powder who wants to be last at the transitions????
2) If using leashes in avy terrain, they MUST break as it is well documented that skis on leads to deeper burial.
3) brakeless  skis can be dropped at transitions.... B&D leashes allow enough extension that I can stick my skis into the snow, tails first and put skins on while they are still attached to my boots.
4) Never had to fart around with taking leashes on and off at transitions due to 3) above. Fastest at transitions means first tracks!!!!
5) I think I still prefer the breakable leash concept to the fiddle factor of dynafit brakes in deep snow. I need to accept that in some falls the link is going to break same as in an avy but that I need to find the correct strength ratio so that they WILL break in an avy but still hold for most falls while skiing.. Maybe double zip ties.?

author=Scotsman link=topic=17741.msg74932#msg74932 date=1288295890]
3) above. Fastest at transitions means first tracks!!!!


Providing that the one that is the first one up lets you go first as a an avalanche probe!

The turns in the middle of the 1st picture look like SauPow's nice tight turns on those new Manaslus  ;)

author=Scotsman link=topic=17741.msg74932#msg74932 date=1288295890]
... I think I still prefer the breakable leash concept to the fiddle factor of dynafit brakes in deep snow. I need to accept that in some falls the link is going to break same as in an avy but that I need to find the correct strength ratio so that they WILL break in an avy but still hold for most falls while skiing.. Maybe double zip ties.?

Might as well go for the triple ties. As far a I know the ties don't really have standardized or rated breaking strength so who knows what you really need or at what actual load each individual tie will break at. The ultimate test will be if (god forbid) you find yourself in an avy and they do NOT break. But in the mean time you'll have had the convenience of items 1 through 4 to justify it. Maybe go with the zip ties that the cops use for handcuffs to lock in those benefits ;)

FWIW, I do not believe my brakes add to my transition time... but then again transition time isn't very important to me, either, so I may be much slower than you regardless. As I’m sure you have noticed, old people are not well known for their fast transitions. On virgin slopes I tend to be more of an “out fumbler”. 



Interesting.
I consider transition times one of the" arts "of BC skiing and very important.
Good transition times result in briefer stops and people not becoming cold etc.
I'm always amazed at how transition times very between people.
There is one person (who shall be nameless) who I toured with who use to touch everything about 3 times and do his transitions in a different sequence nearly everytime. Very slow and frustrating to tour with as a result.
Transitions are one of the few things associated with BC skiing that I frankly do very well and I am very fast  and excuse my chestbeating but I have practised hard and spent the time to develop a sequence that optimizes the movements involved like a "time and Motion " study, so therefore I feel I deserve my self appreciation.
Come up with a sequence and stick to it everytime and touch everything only once.

author=Joedabaker link=topic=17741.msg74933#msg74933 date=1288296694]
Providing that the one that is the first one up lets you go first as a an avalanche probe!

The turns in the middle of the 1st picture look like SauPow's nice tight turns on those new Manaslus  ;)



Actually you are right: FriendlyMarks noodles in the middle. Mine aren't in the picuture. I went further to the looker's right.
Since I now have an ABS pack it thought it was agreed I always get first tracks from now on???

Scotsman:

Interesting to read about your trouble with the B&D leashes. Sounds like there is no perfect solution. While I don't push for first tracks in the bc (there's enough for everybody on most tours) my brakes do drive me nuts sometimes. Most especially when they cause my heel to auto-rotate in deep snow. So obnoxious! Hang on to those leashes if you go back to brakes. I'd like to try them out.


In deep snow you want "Powder Cords" not leashes.

On hard snow or on  the lifts -- you want sturdy leashes or effective brakes. 

But out in avi country, you don't want a leash and brakes are no help in finding a ski lost in deep snow.

Powder cords OTH are long (5-6ft) brightly colored ribbons that clip to your skiis and that you then stuff into the gaiters of your pants -- note they aren't "tied" to your body at all.   

In a fall -- the "ribbon" part tends to stay on the surface and makes it easier to find your skiis after a "yard sale".

In an avalanche -- since the cords aren't tied to you -- your skiis will not act as "anchors".

author=ron j link=topic=17741.msg74921#msg74921 date=1288288948">
The challenges make you stronger young skywalker:
DYNAFIT TLT WIDE BRAKE 130MM


Does anyone know if these can be bent to fit a 138MM ski? I almost lost one of my lotus's (loti?) yesterday, and I'd like for that not to happen.

author=Randy link=topic=17741.msg74944#msg74944 date=1288306283]
In deep snow you want "Powder Cords" not leashes.


Seen people use them but they look a pain in the ass at transitions and I just can't bring myself to go there but thanks for the advice.

author=Scotsman link=topic=17741.msg74939#msg74939 date=1288300574]
Since I now have an ABS pack it thought it was agreed I always get first tracks from now on???


Not if you're going to fall and lose a ski... ;D


I haven't noticed dyna brakes being a nuisance in transition time for me, but I also haven't asked if I was being a nuiance to anyone else.

Sam, not sure if the tolerances hold true on the 130 mm brake, but the FT12 112mm  brake fits over a DPS120.

author=Scotsman link=topic=17741.msg74946#msg74946 date=1288306987]
Seen people use them but they look a pain in the ass at transitions and I just can't bring myself to go there but thanks for the advice.


Yeah -- I can see that -- I guess it is a question of choosing between farting around stuffing the powder cords back into your gaiters after ripping skins vs. sifting around in the snow after "yard sale"

author=samthaman link=topic=17741.msg74945#msg74945 date=1288306598">
Does anyone know if the 130 mm Dynafit brake can be bent to fit a 138MM ski? I almost lost one of my lotus's (loti?) yesterday, and I'd like for that not to happen.


Sam - I'd tend to support Mofro on the matter.

I would hate to see someone blow 80 frogpelts on my say so alone, but were I in your shoes I would go for it and here's my logic:

So you need 4 mm more than advertised on each side of your ski.  That’s like a tad over 3/16 of an inch. You can get at least half that (maybe all of it) by employing Andrew Mclean’s brake arm surgery.  Sometimes the brakes come a bit wider than advertised, anyway. If so you’re set.

IF not you’ll likely need to do a bit of tweaking.  If you need to bend the brake arm out (I have been successful in getting more than a quarter inch more clearance by bending) the trick is to bend just the outer angle. If you just grab ahold of the brake arm and reef on it you will likely change both the inner and outer bend angle of each brake arm. And the trouble with changing the angle in the inner bend is that it changes the geometry of the lateral movement of the brake arm within the frame (like when going from stowed to deployed and vice-versa) and then the brakes don’t deploy properly.

The easiest way I have found to reduce the outer bend angle on the brake arms is to take the brakes off the ski (kind of a pain but worth it) and put just the outer bend of the brake arm in a vice and carefully crank it down to “unbend” or reduce the bend angle the desired amount. Of course when you do this the brake arms don’t stow in as tight as they did before but on superfats like you’re referring to that shouldn’t be a problem.



author=Randy link=topic=17741.msg74959#msg74959 date=1288313061]
Yeah -- I can see that -- I guess it is a question of choosing between farting around stuffing the powder cords back into your gaiters after ripping skins vs. sifting around in the snow after "yard sale"


True but I still can't go there.... I've actually seen people skiing with them trailing behind them.
It's nearly as goofy as those people that have flags on their poles!!!!!! aaaahhh. Makes me shudder.

author=ron j link=topic=17741.msg74937#msg74937 date=1288298120]
Might as well go for the triple ties. As far a I know the ties don't really have standardized or rated breaking strength so who knows what you really need or at what actual load each individual tie will break at. 


Looked up the B&D website and it says "Cable ties(supplied) in vinyl tube provide a breaking strength of approximately 50 lbf and 70 lbf"
How he has derived that data is another question.
So maybe triple ties = 210lbf ...
210lbf is still not a lot of force to cause breakage and I'm pretty sure that if the forces in an avy are strong enough to twist off your bindings even if they are set at DIN 10(  we all rely on that don't we?) then they will break even triple ties. However to get full 210lbf the ties would have to be equalized so that they aren't getting loaded independently.? More research required.

author=Mofro link=topic=17741.msg74957#msg74957 date=1288310574]
I haven't noticed dyna brakes being a nuisance in transition time for me,


See thats just not my experience. I've been complaining about dynabrakes for a long time especially in deep snow. My experience has ALWAYS been that they become problematic in deep snow, get clumped up, ice under the brake ( not to mention the toe-piece) . Not to mention the auto rotation that occurs which is equally if not more annoying.
Brake clumping was happening to my partner yesterday so obviously its not just I who suffer this strange phenomena. When I got rid of the brakes it was like a breath of fresh air and I liked my dynafits much, much more.
I guess my experience of having problems is just as valid as your experience of care-free dynabraking, no?

author=Mofro link=topic=17741.msg74957#msg74957 date=1288310574]
Not if you're going to fall and lose a ski... ;D


The BC bible says" Let he who has not fallen cast the first snowball" ;D

Research on Zip tie strength.


"Our smallest nylon ties (item 17-03) have a 40-pound breaking strength and are not recommended for deer fencing, being better suited to dog fencing and other tasks. The heavier nylon ties (items 17-04 and 17-06) have a breaking strength of 120 pounds, come in both 8-inch and 14-inch lengths, and are suitable for attaching deer fencing to metal posts."

Another link here.
http://www.actfs.com/CatalogProducts.asp?nProductsID=51

So there is data regarding zip tie tensile strength. Now we need to work out some of the forces in a normal fall and the forces that can be induced on skis in an avalanche. How do we do that?
Paging Cookiemonster! Any info on forces within a class 2 avy?

Edit to add: But since we are all relying on our binding releasing in an avy, I don't need to work out the forces in an avy, just the release forces for standard DIN settings and make sure the ties are the same or slightly less than that. if your bindings don't release then it's irrelevant if your zip ties don't break. Since we all assume our bindings will release and those forces are calculable and published ... this is what the zip tie strength should be maximized at to give maximum fall retention while not compromising avy release. Right?

author=Scotsman link=topic=17741.msg74966#msg74966 date=1288318517]
True but I still can't go there.... I've actually seen people skiing with them trailing behind them.
It's nearly as goofy as those people that have flags on their poles!!!!!! aaaahhh. Makes me shudder.


So more of a style issue eh? -- What if the ribbons had a tartan pattern?

author=Randy link=topic=17741.msg74975#msg74975 date=1288325249]
So more of a style issue eh? -- What if the ribbons had a tartan pattern?


Nope, still ain't doing it. Sorry.
Don't care if they were made from woven pubic hair plucked from unicorns! ain't wearing them. nnnoooo way!

Hello All -  weighing in on the side of break away leashes, it seems to me that whatever cable tie connection we settle on, it will need to be a compromise between the sudden loading of that forward launching yardsale vs. the perhaps slower initial loading, hence failure by stretching (yielding?) before snapping which might occur in an avalanche. Any mechanical engineers out there that can weigh in?  Having nearly lost an eye and earned at least 30 stitch's in my scalp from rotating leash attached scythes before the advent of brakes, I still prefer the B & D leash - both for ease of reeling in my fall detached ski, but more importantly, for the security of making fast & comfortable transitions, etc. while still having a ski connected to my leg - particularly on the hard snow & ice of spring summer, or on steeper slopes.  Thanks and keep up the R&D Scotsman!

author=Scotsman link=topic=17741.msg74970#msg74970 date=1288320382]
I guess my experience of having problems is just as valid as your experience of care-free dynabraking, no?


Absolutely Scotsman. I also think the ~5 mm riser plates I have may also allow the brakes to retract better and stay in place such that snow build up is not a problem. My routine involves stepping into the heel before removing skins, which tends to serve me well on transitions. What works for me doesn't mean it will work for you-I also lock my toes out routinely for the down, run a higher DIN per wieght (not calling you names at all- you've got a bit of height and weight on me).

I think you need to be realistic about what you are trying to get out of the leash- strong enough to stay intact during a fall yet still release in an avalanche. My guess is you are talking about a good deal of overlap in the forces given the nature of different falls and different avalanches. I know you are against streamers, but outside of not falling and shedding a ski that really is the most reliable way to find a ski in deep snow.


author=Scotsman link=topic=17741.msg74973#msg74973 date=1288321726]
Paging Cookiemonster! Any info on forces within a class 2 avy?


There isn't really a rule of thumb.

Size 2 involves about 1000 cubic metres of snow, which works out to around 1-5kPa. This is enough to break windows, push in a door, and damage a wood framed structure. These forces are concentrated in the front of the avalanche, and could increase significantly with higher velocity. EX: if the flowing snow were channeled instead of spread out.

I'm not sure about the forces generated during avalanche formation. I assume you are interested in the pressure applied to a ski by the flowing snow during the release of a small slab? A size 2 avalanche was enough to pull a pair of skis off my feet and I was using Fritschi bindings set to 10. That's probably stronger than most zip ties.

Impact Pressures, An Object Lesson:

http://www.nwac.us/media/uploads/documents/accidents/2007_2008/Kahler_Glen_Incident_2_7_08.pdf

OK thats what I wanted to hear and confirms my theory, at least to me.
If a class 2 can suck off a pair of Fritschi's set at DIN 10, then the zip-ties on the leashes can be maximized to resist at least that force without causing concern that they won't break.( if the skis don't come off the zip ties are irrelevant)

I need to understand the forces relating to DIN 10 release to size the zip ties.

I also think the zip ties can be far stronger than people think and still have confidence in breaking as once the bindings release, the skier and skis will tend to separate in the turbulent flow of the avy because of different size and shape ratios. This will cause considerable forces on the zip ties similar to the shock loading achieved in a yard sale.
What do think about that theory Cookie?

author=Scotsman link=topic=17741.msg74987#msg74987 date=1288333485]
I also think the zip ties can be far stronger than people think and still have confidence in breaking as once the bindings release, the skier and skis will tend to separate in the turbulent flow of the avy because of different size and shape ratios. This will cause considerable forces on the zip ties similar to the shock loading achieved in a yard sale.
What do think about that theory Cookie?


This reply is long because I'm trying to be thorough.

1. Separation of Skier & Skis

Yes, I think the skiers and skis would tend to separate for the reason you describe. If I recall correctly, granular flow is an example of convective behaviour in particulate matter ( aka the Brazil Nut effect ). Assuming the skier and skis are decoupled, then it seems very reasonable to expect that sort of separation in the turbulent flow regime of the avalanche.

Anyway, Alec van Herwijnen et al. ( WSL ) described this effect as "the capacity for particles to rearrange themselves" and he used the example of tapping a tin of ground coffee on a counter so that you can get a little more space inside in the tin for more coffee. And further, we've all seen turbulence separate particulate matter into groups of different sized pieces.

*

2. Forces

I've heard of avalanches snapping climbing ropes during belayed ski cuts, but I couldn't find any specific examples, nor any specific data on the size of the avalanches or the forces involved. It occurs to me that Bruce Tremper discusses this somewhere in "Staying Alive in Avalanche Terrain". For this reason, I don't think an avalanche would have any trouble breaking a zip tie, but the consequences of staying attached to your skis in an avalanche are *very* bad. ( I know a few professionals and at least one high-end researcher who won't use Dynafits for this exact reason. )

I really don't know the appropriate strength for a zip tie in this application. Does anyone have any idea about the force required to pop a Fritschi binding at 10? Could this force be converted to a weight that could be used in a drop test? The Black Diamond web site is always showing hanging / drop tests used to test the strength of climbing gear. I think if you want to be really safe then you might want to see how much weight the zip tie can support in a drop test.

I'm not sure a drop test would give relevant results for an avalanche and stress on a zip tie.
In the several avalanches I have had the misfortune to experienced in my life. I have to compare and think that the static test that you gave earlier would have the best results of actual involvement. I have been involved in some doozies. I'm not saying that the information from a series of drop tests would not form some relevant means.
Kam would have the best means to this type of research given U of Nevada probably has testing for static tension tests that can go as far as reading/graphing the elongation in tension before failure.

On a personal side the toepieces on the Dynafits are in between for me. If I have them set on low tension they just fall off while skiing or hiking. Like MoFro I have to lock them in just to stay in them. SO I guess in our case it won't make a lick of difference so I lean to the leash.

author=Joedabaker link=topic=17741.msg74993#msg74993 date=1288366802]
I'm not sure a drop test would give relevant results for an avalanche and stress on a zip tie.
In the several avalanches I have had the misfortune to experienced in my life. I have to compare and think that the static test that you gave earlier would have the best results of actual involvement. I have been involved in some doozies. I'm not saying that the information from a series of drop tests would not form some relevant means.
Kam would have the best means to this type of research given U of Nevada probably has testing for static tension tests that can go as far as reading/graphing the elongation in tension before failure.

On a personal side the toepieces on the Dynafits are in between for me. If I have them set on low tension they just fall off while skiing or hiking. Like MoFro I have to lock them in just to stay in them. SO I guess in our case it won't make a lick of difference so I lean to the leash.



You might be right about the inapplicability of the drop test. To acquire useful data, two tests are required: a drop test ( impulse load ) and a pull test ( gradual load ) to determine the force required to release a given zip tie.

For some reason, and this is total speculation on my part, I think there is a chance that a gradual load over a few seconds might not produce failure quickly enough, and even a few seconds delay could result in the skier being entrained in the flowing snow.

Ideally, in the event of an avalanche you want instantaneous decoupling from the skis. I bet the zip tie plastic will be cold and much more susceptible to brittle fracture than if it were warm. Maybe, at a minimum, brittle plastics would be better for this application.

As you mention, this is fairly moot if your toe is locked. I weigh 95 kilos, so my toes are always locked when climbing.

Ummmmmmm...,  What the "H" are you guys talking about?

I looked at my bindings, and they have a cable thingy with a flipiddy-doo on the back.  I read the owner's manual, and it didn't say anything about "release" or this "DIN" thing you keep referring to.  Is this bad?

I use Zip ties to fix the cable thingy when it breaks occasionally, and I sometimes put a "leash" on my dog Chinook when he goes skiing with me and Nazi-dog-hater-skiers are around.

"Brakes" ??? WTH? Do your skis have a steering wheel too?

I'm confused,

But I am intrigued by this pursuit of a binding/ski/leash/brake/chord set-up that releases in a class II or higher avalanche or a nasty fall, but not a fall in powder, unless its a REALLY nasty fall in powder and the skis have trustworthy brakes...

Also, do powder chords come in orange?  I'd prefer they match my gloves.

Oh, and what does any of this have to do with Crystal Southback Pow?

^^^^^^ Yeah well you teleheads better get releasable bindings is all I have to say. ;) Always concerns me when I'm with a telehead in Avy terrain. Very well documented that skis on= much deeper burial=less survivability.
But you all know that already!

I'm pretty convinced that the zip-ties can be way stronger than people think and still reliably break in the forces expected in an avy.
What I have discovered is that the zip- tie always fails at the clasp unless it has been cut.
I intend to do some experimenting with some strain gauges we have here at work and see what the result are.

author=Scotsman link=topic=17741.msg75005#msg75005 date=1288374960]
What I have discovered is that the zip- tie always fails at the clasp unless it has been cut.


That is not surprising to me at all. Climbing ropes can fail at knot points because of significantly higher stress concentrations. I imagine this is the case with zip ties as well.

author=kneel turner link=topic=17741.msg75000#msg75000 date=1288372883]
I sometimes put a "leash" on my dog Chinook when he goes skiing with me and Nazi-dog-hater-skiers are around.



I had Chugach my Husky with me in the South Back this day and he got really tired by the end of the day due to all the postholing.
He gets back home and tells my wife Pam.
( in doggy language of course)
" Some best friend he's turned out to be... first he cuts off my balls... and then he makes me posthole in deep powder for 6 hours"
He then went unconscious on the floor and made" revenge farts" all night.

I saw his prints on my way up.  Was 20 minutes behind you.  Got me thinking about buying a pup soon. I  have not been able to do it since mine died 15 yrs ago.  It was a good day.

author=Clawskinner link=topic=17741.msg75057#msg75057 date=1288463828]
I saw his prints on my way up.  Was 20 minutes behind you.  Got me thinking about buying a pup soon. I  have not been able to do it since mine died 15 yrs ago.  It was a good day.


Yea I understand. Took me years to get over the early death of my beloved Boris, a Great Dane I had.
Touring with your dog can be so rewarding. I love it.
Get your puppy.

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7860
oct-27-crystal-southback-pow
Scotsman
2010-10-27 16:52:57