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#21
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Distance of the 3 Vallees Route
On Wed, 11 Feb 2004 13:58:38 +0100, Ace wrote:
On Wed, 11 Feb 2004 12:50:50 +0000, Steve Haigh wrote: Crosbie Fitch wrote: "helloblondie" wrote in message ... I have a very accurate map! The distance is exactly 62.5 miles well done guys! But, is that taking into account the ups and downs? If not, one should add 10-40% to the distance depending upon the gradients of the slopes traversed. Nothing like. Add at most 5 or 6%. If you are skiing on normal pistes with a mix of blue/red/black you are unlikely to exceed a 20 degree gradient on average over the day. 30 degrees would be an extremely steep black. It doesn't sound like a lot, but I can't think of a marked piste in the 3V that exceeds that (including the couloirs in Courchevel). 30deg would give a ration of 1:1.15, i.e. a 15% difference. 20deg gives just less than 10% diff. And yes, this would be a steep average for a day. I find that statement extremely surprising. Most piste maps don't seem to give run lengths, but from those that do (such as Soldeu-El Tarter), or where the "longest run" is a red (such as the Planai, Schladming), it seems that most red runs average round about 20% gradient (a 1km vertical will be around 5km pistes length). So if you stuck to red runs all day, you could expect to be averaging around 20%. But I'm not sure where you get your 10% for 20 degrees and 15% for 30 degrees from. I think the original statement of 10-40% had an upper limit somewhat too high, but I would suggest anything from 10-30% is not impossible. -- Alex Heney, Global Villager URA Redneck if your dog can smoke a cigarette. To reply by email, my address is aDOTjDOTheneyATbtinternetDOTcom |
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#22
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Distance of the 3 Vallees Route
On Wed, 11 Feb 2004 14:28:38 +0000 (UTC), Alex Heney
wrote: On Wed, 11 Feb 2004 13:58:38 +0100, Ace wrote: Crosbie Fitch wrote: If not, one should add 10-40% to the distance depending upon the gradients of the slopes traversed. 30deg would give a ration of 1:1.15, i.e. a 15% difference. 20deg gives just less than 10% diff. And yes, this would be a steep average for a day. I find that statement extremely surprising. Most piste maps don't seem to give run lengths, but from those that do (such as Soldeu-El Tarter), or where the "longest run" is a red (such as the Planai, Schladming), it seems that most red runs average round about 20% gradient (a 1km vertical will be around 5km pistes length). So if you stuck to red runs all day, you could expect to be averaging around 20%. But I'm not sure where you get your 10% for 20 degrees and 15% for 30 degrees from. Hopefully the explanation I posted up there ^ should help. I think the original statement of 10-40% had an upper limit somewhat too high, but I would suggest anything from 10-30% is not impossible. A 30% difference would mean that your distance travelled was 1.3 times the horizontal distance, yes? So, using the Cosine rule as before, that would give an average slope of 40deg. So not impossible per se, but not possible in any resort I've ever found :-) -- Ace (brucedotrogers a.t rochedotcom) Ski Club of Great Britain - http://www.skiclub.co.uk All opinions expressed are personal and in no way represent those of the Ski Club. |
#23
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Distance of the 3 Vallees Route
"Alex Heney" and many others wrote in message ...snipsy ... If not, one should add 10-40% to the distance depending upon the gradients of the slopes traversed. Doesn't this assume that you ski everything straight down the fall line? Sod that! - in my case I'll need to add at least twice as much again for all the traversing. No wonder I feel so tired at the end of the day - I must ski miles more than you guys! -- Paul Schofield Time flies like an arrow Fruit flies like a banana |
#24
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Distance of the 3 Vallees Route
On Wed, 11 Feb 2004 14:37:18 -0000, "Paul Schofield"
wrote: "Alex Heney" and many others wrote in message ..snipsy ... If not, one should add 10-40% to the distance depending upon the gradients of the slopes traversed. Doesn't this assume that you ski everything straight down the fall line? Sod that! - in my case I'll need to add at least twice as much again for all the traversing. No wonder I feel so tired at the end of the day - I must ski miles more than you guys! Good point. -- Ace (brucedotrogers a.t rochedotcom) Ski Club of Great Britain - http://www.skiclub.co.uk All opinions expressed are personal and in no way represent those of the Ski Club. |
#25
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Distance of the 3 Vallees Route
On Wed, 11 Feb 2004 15:35:36 +0100, Ace wrote:
On Wed, 11 Feb 2004 14:28:38 +0000 (UTC), Alex Heney wrote: On Wed, 11 Feb 2004 13:58:38 +0100, Ace wrote: Crosbie Fitch wrote: If not, one should add 10-40% to the distance depending upon the gradients of the slopes traversed. 30deg would give a ration of 1:1.15, i.e. a 15% difference. 20deg gives just less than 10% diff. And yes, this would be a steep average for a day. I find that statement extremely surprising. Most piste maps don't seem to give run lengths, but from those that do (such as Soldeu-El Tarter), or where the "longest run" is a red (such as the Planai, Schladming), it seems that most red runs average round about 20% gradient (a 1km vertical will be around 5km pistes length). So if you stuck to red runs all day, you could expect to be averaging around 20%. But I'm not sure where you get your 10% for 20 degrees and 15% for 30 degrees from. Hopefully the explanation I posted up there ^ should help. Yes. It did, thanks. I understand what you are saying now, and agree with you. I (and I suspect the OP as well) was wrongly over-simplifying, and just adding vertical to horizontal to get total distance. And I was misreading what you wrote, thinking you were equating a 30 degree slope to a 15% slope, which is of course way low. -- Alex Heney, Global Villager I am, therefore I am (I don't draw conclusions). To reply by email, my address is aDOTjDOTheneyATbtinternetDOTcom |
#26
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Distance of the 3 Vallees Route
Maybe I should also ask if this 'distance skied' includes the very steep
chair-lifts/cable-cars? I presume it doesn't. NB I was guessing at around 45 degrees for snow adhesion as my upper bound, hence root 2, hence 1.414, hence ~40%. |
#27
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Distance of the 3 Vallees Route
On Wed, 11 Feb 2004 16:07:31 +0000 (UTC), "Crosbie Fitch"
wrote: Maybe I should also ask if this 'distance skied' includes the very steep chair-lifts/cable-cars? I presume it doesn't. NB I was guessing at around 45 degrees for snow adhesion as my upper bound, hence root 2, hence 1.414, hence ~40%. I'm curious as to how you remembered that sin/cos45 was 1/root2. Not the sort of thing that sticks in most people's minds, I'd have thought:-) Or is there a much simpler theorem that I've forgotten? -- Ace (brucedotrogers a.t rochedotcom) Ski Club of Great Britain - http://www.skiclub.co.uk All opinions expressed are personal and in no way represent those of the Ski Club. |
#28
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Distance of the 3 Vallees Route
Ace wrote:
Imagine the horizontal, or map distance represented by the base of a triangle, whose hypotenuse would then be the distance travelled over the snow. Schoolboy geometry tells me that the cosine of the angle between these is equal to the length of the base divided by the length of the hypotenuse. So if I ski 1 mile at an average slope of 30deg, the actual distance skied would be 1/cos30, which is 1.15 miles, a 'difference' of 15%. Hope it's clear now. Doh. Yes, sorry, thats clear enough. Ta. I was just talking at cross purposes with myself I think. |
#29
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Distance of the 3 Vallees Route
Crosbie Fitch wrote:
Maybe I should also ask if this 'distance skied' includes the very steep chair-lifts/cable-cars? Dunno, but FYI cable cars can climb stunning gradients (e.g. the Aig du Midi top stage must be 45 degrees if not more). Chair lifts can ascend much less steeply, I don't know the upper limit but I can't recal riding a chair that averages anything like 45 degrees. I presume it doesn't. Actually, I think I'm long past caring:-) NB I was guessing at around 45 degrees for snow adhesion as my upper bound, hence root 2, hence 1.414, hence ~40%. Depending on where you are in the world the upper-limit for snow adhesion (and I mean snow, not ice forming due to condensation etc) varies. For reasons I do not fully understand snow sticks to very steep slopes in the Andes (e.g. over 70 degrees), so the extent that climbing some peaks involves swimming almost verticaly through massive amounts of soft snow (nopt something I've done myself, but a few friends have). I guess such conditions make for spectacular avalanches too. In Alaska and the west coast of BC snow seems to accumulate on very steep slopes also. It is certainly possible to ski powder at an angle over 50 degrees sustained over a long pitch. I'm told it's due to the humidity as these areas are very close to the Pacific. I'm not sure about the alps, but I know snow is "dryer" and sticks less easily so 45 degrees is a reasonable guess for the steepest slope on which snow can accumulate in skiable amounts, but I do not know of any pistes which get anywhere near this. And if I managed to cover 67km in a day on such a slope I would be pretty chuffed and pretty knackered [and probably lying]. |
#30
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Distance of the 3 Vallees Route
Ace wrote:
I'm curious as to how you remembered that sin/cos45 was 1/root2. Not the sort of thing that sticks in most people's minds, I'd have thought:-) Or is there a much simpler theorem that I've forgotten? Pythagoras? |
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