Author Topic: Ski trail ratings  (Read 676 times)

jim-ratliff

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Ski trail ratings
« on: March 01, 2011, 12:06:20 pm »
I finally got around to creating my Vail on-line account that allows me to view activity.? In 10 days of skiing at their electronically enabled resorts, I have 115,000 vertical feet.? That includes a couple of days with 17,000 vertical and a couple with less than 5,000.? 17,000 per day is nothing to brag about, there are some that do 40-80,000 per DAY.

But that got me wondering, "if that was the number of feet of vertical, then how many miles of skiing have I done?"? And that led me to Wikipedia, where I found the following really astonishing nugget (this is the link? http://en.wikipedia.org/wiki/Alpine_skiing ).? In my mind, I had always assumed that there was a closer coorelation between %slope and degree slope, but not so.? Here is what I think they are saying.? On highways, an 8% grade means that the road goes down (or up) 8 feet for every 100 feet horizaontal.? A 100% gradient (or slope, in this case) is one where it drops 100 feet vertical for every 100 feet horizontal.

Quote from: wikipedia
Green - The easiest slopes at a mountain. Green Circle trails are generally wide and groomed, typically with slope gradients ranging from 6% to 25%[1] (a 100% slope is a 45 degree angle).
Blue - Intermediate difficulty slopes with grades commonly ranging from 25% to 40%. These slopes are usually groomed. Blue Square runs make up the bulk of pistes at most ski areas, and are usually among the most heavily trafficked.
Balck - Amongst the most difficult at a given mountain. Black Diamond trails tend to be steep (typically 40% and up)[1] and may or may not be groomed, though the introduction of winch-cats has made the grooming of steep slopes both possible and more frequent.

I find I can visualize degrees better than gradients or percent slopes, and I think this difference has popped up in some discussions about how steep given slopes are.? A 30 degree slope is MUCH steeper than a 30% gradient.

10%? =? 5.7 degrees
20%? = 11.3 degrees
30%? = 16.7 degrees
40%? = 21.8 degrees
50%? = 26.6 degrees
75%? = 36.9 degrees
100% = 45 degrees

The steepest railroad grade in the US is Cass Scenic Railroad in West Virginia at 11%, and it seems really steep going up.? I think most railroads try to maintain a grade of less than 1% (a 1% grade doubles the load on the engine, no wonder 6% grades kill me when biking).
« Last Edit: March 01, 2011, 12:27:26 pm by jim-ratliff »
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jim-ratliff

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Re: Ski trail ratings
« Reply #1 on: March 01, 2011, 12:24:42 pm »
So if I have averaged 25% slopes (the low end of blue), then I have 100 feet of horizontal for every 25 feet of vertical.

The hypotenuse of a right triangle with a 25 vert by 100 hor base is (5+10) squared = 225 feet.

So my 115,000 feet of vertical gives me (approximately) 1,035,000 feet or 196 miles of skiing.

 ;D ;D ;D OK, so its a slow day at work and I'm looking forward to leaving for skiing soon.? ;D ;D ;D


I need Todd or an engineer to check these numbers, because 200 miles seems like a lot.? >:D :'(
« Last Edit: March 01, 2011, 12:31:35 pm by jim-ratliff »
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jim-ratliff

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Re: Ski trail ratings
« Reply #2 on: March 01, 2011, 12:48:02 pm »
 Days at A-Basin, Elk (2), Mad River Glen, Sol Vista, and Sugar Bush (2) not included.

Can you imagine how many feet of vertical some of you who ski better than me have racked up at big mountains, like Ron and his cat skiing trip or on your trips to Jackson Hole?
« Last Edit: March 01, 2011, 03:57:19 pm by jim-ratliff »
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LivingProof

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Re: Ski trail ratings
« Reply #3 on: March 01, 2011, 01:14:23 pm »
Jim,

After all the work you did for me to demo you skis, I hate to be the person that bursts your bubble, but......your math is incorrect.

100 x 100 = 10000
  25 x  25  =    625
Total        =  10625

Sq. root of 10625 = 103.0

So your 115,000 vertical feet yields only 118,000 ski trail feet or 22 miles

Just go skiing with Lynn and enjoy the view(s).

ToddW

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Re: Ski trail ratings
« Reply #4 on: March 01, 2011, 02:13:10 pm »
Jim,

A roughly 90% reduction in length must be pretty traumatic for you, but you're man enough to cope.  As he said, just go skiing with Lynn and enjoy the view(s).

jbotti

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Re: Ski trail ratings
« Reply #5 on: March 01, 2011, 03:24:51 pm »
If you want to spend $500 on the new GPS goggles, it will tell you how much vert, avg/top and low speed as well as miles skied each day and after each run. Seems easier than trying to calculate it yourself. A friend on mine has them and I hear all the stats after each run. Kind of fun. Not sure I love the price, for info that I don't really care about. But in case you care there is a $500 solution!

jim-ratliff

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Re: Ski trail ratings
« Reply #6 on: March 01, 2011, 03:39:31 pm »
MIke -- Thanks for the correction.

Ohh, that's embarrassing.  I did the right triangle calculation backwards.  I took the root of the two legs, added them together and squared that.  Thanks for the correction -- and the bursting bubble.  3-4-5 = 9+16=25.  CRAP.

John, I'll pass on the goggles.  This is kind of interesting as I sit here in Virginia watching Lynn rack up vertical at Beaver Creek, but the woman she is attending the conference with only does groomed slopes and likes to ski them fast.  I don't think total vertical tells me much about how much fun I had or what the trees or bumps or powder was like.

But I have to admit to being impressed by the guy on the "leaderboard" that has 105 days on the snow and 4.25 million vertical feet.  I can't find a day that he hasn't been out and racked up 40-60,000 feet.
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jim-ratliff

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Re: Ski trail ratings
« Reply #7 on: March 01, 2011, 03:40:45 pm »
Jim,

A roughly 90% reduction in length must be pretty traumatic for you, but you're man enough to cope.? As he said, just go skiing with Lynn and enjoy the view(s).

Todd:? If you inflate the numbers enough in the beginning, then a 90% reduction is still a very satisfying length.? ?;D
I can be happy with 22 miles.

Leaving to join Lynn at Beaver Creek after work on Thursday thru next week; she's out there this week as well.
« Last Edit: March 01, 2011, 04:05:33 pm by jim-ratliff »
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jim-ratliff

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Re: Ski trail ratings
« Reply #8 on: March 01, 2011, 03:43:09 pm »
If you want to spend $500 on the new GPS goggles, it will tell you how much vert, avg/top and low speed as well as miles skied each day and after each run. Seems easier than trying to calculate it yourself. A friend on mine has them and I hear all the stats after each run. Kind of fun. Not sure I love the price, for info that I don't really care about. But in case you care there is a $500 solution!

And then I'd feel really crappy the first time a tree limb whacked them and they just became "goggles".
Besides, there should be an app for that for my HTC Evo soon??? As long as I carry a back pack of batteries to keep it running all day.

Actually, I haven't checked but I assume that there are wrist watches (such as some bike riders use) that would give you some of that information and let you download it into the computer at night (if you don't have anything better to do after a good day of skiing).
« Last Edit: March 01, 2011, 03:45:25 pm by jim-ratliff »
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LivingProof

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Re: Ski trail ratings
« Reply #9 on: March 01, 2011, 03:45:55 pm »

Quote from: wikipedia

Blue - Intermediate difficulty slopes with grades commonly ranging from 25% to 40%. These slopes are usually groomed. Blue Square runs make up the bulk of pistes at most ski areas, and are usually among the most heavily trafficked.

Balck - Amongst the most difficult at a given mountain. Black Diamond trails tend to be steep (typically 40% and up)[1]

The above numbers a not accurate, not a surprise as Wikipedia is not known for the truth, whole truth etc.

In the east, only the very steepest trails approach 40 degrees (not slope). The front 4 at Stowe are high 30's. Trust me, those 4 are very expert.

In the Rockies, Palavencini at A-base is known to be just over 40 degrees over it's length.

For very short pitches, may trails have plus 40 degrees.



jim-ratliff

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Re: Ski trail ratings
« Reply #10 on: March 01, 2011, 03:49:09 pm »
Jim,

After all the work you did for me to demo you skis, I hate to be the person that bursts your bubble, but......your math is incorrect.

100 x 100 = 10000
? 25 x? 25? =? ? 625
Total? ? ? ? =? 10625

Sq. root of 10625 = 103.0

So your 115,000 vertical feet yields only 118,000 ski trail feet or 22 miles

Just go skiing with Lynn and enjoy the view(s).

Uh-oh, now this is getting sad.? ?;D ;D

Mike, what is the calculation that gives you 118,00 ski trail feet from your numbers?

As you said, for every 25 feet of vertical, I get 103 feet of ski trail feet (not my 225)?
However,? 115,000 / 25 * 103 = 473,800 ski trail feet, and 90 ski trail miles.

And, Todd, that means I only lost 54% of my length. (whew  8) )

By the way, if I'm wrong again in my math, I plan to ban myself from the forum.? ?;D
And I can't wait for Lynn to read this, I can see her rolling her eyes already.
And laughing hysterically at guys in general.
« Last Edit: March 01, 2011, 04:06:38 pm by jim-ratliff »
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meput

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Re: Ski trail ratings
« Reply #11 on: March 01, 2011, 06:04:48 pm »
All of you have way too much free time at work? >:D. I think you all need to take a day off from work and get your skiing fix.

I am glad I do not have any kind of mathematical or engineering background? :D. Those of us in medicine know numbers lie (statistics). My accountant also says numbers can tell you anything you want? ???.

Just go skiing and enjoy !!! ;D ;D

meput

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Re: Ski trail ratings
« Reply #12 on: March 01, 2011, 06:20:53 pm »
Jim,

Just downloaded "Ski Tracks" app for my iphone. Will try it out this weekend and let you know. If it works well, you may need to trade in the htc.

Jim


LivingProof

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Re: Ski trail ratings
« Reply #13 on: March 01, 2011, 07:21:56 pm »
Jim,

After all the work you did for me to demo you skis, I hate to be the person that bursts your bubble, but......your math is incorrect.

100 x 100 = 10000
? 25 x? 25? =? ? 625
Total? ? ? ? =? 10625

Sq. root of 10625 = 103.0

So your 115,000 vertical feet yields only 118,000 ski trail feet or 22 miles

Just go skiing with Lynn and enjoy the view(s).

Uh-oh, now this is getting sad.? ?;D ;D

Mike, what is the calculation that gives you 118,00 ski trail feet from your numbers?

As you said, for every 25 feet of vertical, I get 103 feet of ski trail feet (not my 225)?
However,? 115,000 / 25 * 103 = 473,800 ski trail feet, and 90 ski trail miles.

And, Todd, that means I only lost 54% of my length. (whew? 8) )

By the way, if I'm wrong again in my math, I plan to ban myself from the forum.? ?;D
And I can't wait for Lynn to read this, I can see her rolling her eyes already.
And laughing hysterically at guys in general.


Jim,
Two wrongs and we finally got it right.

I looked at Blue Mountains website. Their 6 pack chair rises 1050 feet and the chair length is 4300 feet, so very roughly it conforms to your 4 to 1 length to height (100 to 25) model. An approximation is that one run is 5200 feet of skiing or about 1 mile. (Some are shorter or longer). So skiing 20 miles per 4 hours is reasonable based on 5 runs per hour.

Now, damnit, go skiing with Lynn and enjoy the views.  ;D And do the drills ::)

In my younger days of skiing, I worried about how much vertical I did skiing. My skiing mentor always told me to worry much more about how much horizontal I got at night. But that was a long time ago.

ToddW

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Re: Ski trail ratings
« Reply #14 on: March 01, 2011, 08:10:15 pm »
Sorry, Jim #1.? I didn't know you and Lynn would be at BC this week.? I think I skied all the snow off of their mountains last Saturday.? If I'd only known, I would've left a dusting for you.? Don't worry, even if there's no snow left there will still be free chocolate chip cookies? ;D

Jim #2, what a great therapeutic recommendation!? Can I show your note to my employer as a "doctor's note?"? ?I haven't been on snow for two days and am in deep withdrawal.