Distance of the 3 Vallees Route

James Hart wrote:
Ace wrote:

On Wed, 11 Feb 2004 13:59:48 +0000, Steve Haigh
wrote:


Ace wrote:

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 think we may be talking at cross purposes here - the % I mean when
I say 5 or 6% is the amount to add to the horizontal distance
travelled to get the "true" distance covered - I assumed this is
what was meant by "helloblondie" when suggesting adding 10-40% to
the distance.

That's exactly what I assumed.


I.e. if you measure the distance on a map I think you need to add
about 5% to the figure to give the actual distance covered to
include the extra due to going up and down. Of course if you did
speed the whole day on super steep runs you may need to add more.

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.


Righty ho, you've skied 1.15 miles on that 1 mile run but what about me, zig
zagging my way along at a reasonable pace or my friends merrily snow
ploughing away behind me doing 50 yards across the piste for every 20 yards
they're doing down the piste? Is there any rough 'n' ready reckoning for
working this into the equation?

Not sure how close this is, but the ratio of the length of a river to
the actual distance covered as the crow flies is approximately PI/2.
I.e. the real length of a river is is 1.57 times the straightline
distance from the source to the sea.

So, I guess if you were making lots of nice linked turns you could
assume a similar ratio for the distance you covered.

However, if you are traversing you'll do way more than this... trouble
is we'd need to know the angle of the traverse. If the angle was 15
degrees (so at the end of each traverse the angle between the upper and
lower traverse is 30 degrees, which sounds about right) then for each
metre of "straight" distance you will have travelled 3.86m. So call it 4
times as much distance to make life easier.


I reckon most of my troop would have been skiing double the length of most
slopes compared to the straight line approach and have guessed an average
day's skiing at about 10-15 miles per day. Would this sound about right for
a bunch of late 20 somethings doing most of the day on blues and reds going
at the pace of the slowest at about 2 weeks experience?
We sat down with the map and were trying to come up with a 'real' figure
based on the piste figures.

Double the length if you are skiing with mostly linked turns and the odd
traverse sounds like a good approximation.

Ace wrote:

On 11 Feb 2004 11:48:39 -0800, (Plake)
wrote:


I know according to the Good Skiing Guide/Where to Ski a few years ago
that the Couloir sous la Telepherique at Courchevel was the steepest
piste in Europe, at 38 degrees, although I think it's recently been
changed to an off-piste route.


Sorry, but that's absolute cobblers. I've measured[1] many pistes

40deg, including the Aigle black run in Flaine, which I specifically

remember being 42deg on the first 'drop-in' pitch. I'm sure that's not
'the steepest' either.

[1] My compass has a clinometer built in.

I didn't get a chance to ski this when I was there but it sounds like a
decent challenge!

But, you mention it was 42 degrees for the drop-in, does it average 42
degrees for the whole run? I guess (but I don't know) that the Couloirs
refered to by the GSG were averageing 38 degrees.

If you are going to measure the angles of individual pitches there will
be a lot more in the 40 degree + category. If you count dropping off a
cornice there may even be pitches of more than 90 degrees:-)

Ace wrote:

On Wed, 11 Feb 2004 16:48:33 +0000, Steve Haigh
wrote:



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),


West coast American (and I presume by extension south american) snow
tends to be much drier that we're used to in Europe, which means it
weighs less
Not in Whistler it isn't, and in California the term Sierra Cement is
more often heard than powder:-) IME it is very wet on the coast (not
tried Alaska though, I think the cold may keep it drier) and although
deep soft snow is common it is pushing it to call it powder somtimes.

In the Rockies the snow is much drier, as you say, and therefore lighter.

On Thu, 12 Feb 2004 12:19:23 +0000, Steve Haigh
wrote:

Ace wrote:

40deg, including the Aigle black run in Flaine, which I specifically

remember being 42deg on the first 'drop-in' pitch. I'm sure that's not
'the steepest' either.

[1] My compass has a clinometer built in.

I didn't get a chance to ski this when I was there but it sounds like a
decent challenge!

But, you mention it was 42 degrees for the drop-in, does it average 42
degrees for the whole run? I guess (but I don't know) that the Couloirs
refered to by the GSG were averageing 38 degrees.

The top steep pitch, of approx 150? metres, is all around that
gradient, but there's a flat access bit above it and one or two
flattish bits further down, particularly where it crosses the blue
run. The bottom part is probably a similar gradient, though.

If you are going to measure the angles of individual pitches there will
be a lot more in the 40 degree + category. If you count dropping off a
cornice there may even be pitches of more than 90 degrees:-)

True, but by 'pitch' I was meaning to imply 'a significant chunk of
skiing', IYSWIM.

--
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.

Ace wrote:
The top steep pitch, of approx 150? metres, is all around that
gradient, but there's a flat access bit above it and one or two
flattish bits further down, particularly where it crosses the blue
run. The bottom part is probably a similar gradient, though.

Have you not measured it ? I thought, if forced to guess, that the
bottom was slightly steeper maybe.

On Thu, 12 Feb 2004 14:54:56 +0100, Ian Spare
wrote:

Ace wrote:
The top steep pitch, of approx 150? metres, is all around that
gradient, but there's a flat access bit above it and one or two
flattish bits further down, particularly where it crosses the blue
run. The bottom part is probably a similar gradient, though.

Have you not measured it ?

I may have a clinometer with me most of the time, but I'm not actually
in the habit of measuring every bit of snow I ski. Ususally I have
better things to do with my time, like actually skiing it :-)

I thought, if forced to guess, that the
bottom was slightly steeper maybe.

Hmmm, not sure about that. I alwys thought the top bit looked steeper,
but it could just be an optical illusion, as it's just got the sky
above it.

--
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.

Ace wrote:

Hmmm, not sure about that. I alwys thought the top bit looked steeper,
but it could just be an optical illusion, as it's just got the sky
above it.


it just crossed my mind the other week, "crikey, this is steep" I
thought just as a 'blader cartwheeled past :-)

I only reported what the book said! I think the confusion stems from
the fact that the couloir is the steepest in terms of overall pitch
top to bottom - virtually all other black runs have flatter bits
somewhere so the average gradient comes down. Even straightforward
blacks occasionally have very short sections that are seriously steep
- there's a bit like this on the Wengen Lauberhorn run for example.

Al

Ace wrote in message . ..
On 11 Feb 2004 11:48:39 -0800, (Plake)
wrote:

I know according to the Good Skiing Guide/Where to Ski a few years ago
that the Couloir sous la Telepherique at Courchevel was the steepest
piste in Europe, at 38 degrees, although I think it's recently been
changed to an off-piste route.

Sorry, but that's absolute cobblers. I've measured[1] many pistes
40deg, including the Aigle black run in Flaine, which I specifically
remember being 42deg on the first 'drop-in' pitch. I'm sure that's not
'the steepest' either.

[1] My compass has a clinometer built in.

Plake wrote:
I only reported what the book said! I think the confusion stems from
the fact that the couloir is the steepest in terms of overall pitch
top to bottom - virtually all other black runs have flatter bits
somewhere so the average gradient comes down. Even straightforward
blacks occasionally have very short sections that are seriously steep
- there's a bit like this on the Wengen Lauberhorn run for example.
Yep, I think you may be right, in terms of the average over the whole
run maybe they are the steepest. The piste map (IIRC) has the blacks
running from the top but joining a blue or red fairly soon after the
couloirs finish, hence the range over which they measure the gradient of
the black run is short and all of it quite steep. Most other blacks will
have longer less steep sections and hence lower overall gradients.

Ace wrote:
Ian Spare

I see that FaceWest sell the Orotovox Inclinometer :

http://www.facewest.co.uk/Products%2...ccessoreis.htm

Got one built-in on my compass (Suunto). Much easier.


You will find all the very best skiers carry a Suunto
compass/clinometer.