What is the maximum gradient of a piste slope (in degree)?

A snowHead

Someone has commented on a post that a snowmobile will fall off a 65 degree slope. I know European black slopes are seldom groomed. Does anybody know the maximum gradient (in degree if possible) beyond which it cannot be groomed by a machine?

Also do people grade black slopes according to a gradient? Have seen 60 to 70 degrees slopes being mentioned in piste maps and extreme skiing videos were talking about slopes with more than 80 degrees. What is the maximum known gradients in the published piste maps and where?

A snowHead

saikee, at Eldora, there is a section of trees that is rumored to be 60+ degrees.

In the US, very steep trails are groomed by winch-cat. They effectively use a winch to pull the cat up the slope to groom the piste. At Beaver Creek they do this on the "Birds of Prey" which are in that same range, I think.

Well, the person's real but it's just a made up name, see?

Most very steep European blacks are only about 35-40 degrees, some off-piste and US double-blacks are steeper of course, but anything above 45 degrees can be considered extreme i.e. in most conditions, if you fall you are in big trouble! I'm not sure what the real extreme guys can cope with nowadays, but I think the likes of Tardivel etc have done 65-70 degree slopes. Boarders do this kind of thing best - with an ice-axe in each hand!

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the maximum gradient beyond which it is practically impossible to groom is 90 degrees. After that, the laws of gravity dictate that the grooming machine will not put pressure on the slope, but will fall away from it. snowHead

Anyway, snowHeads is much more fun if you do.

AT Apostle wrote this very good guide on Telemark Tips

Steep-speak International Translations:

France: Subtract 5 degrees & 1/3 of the stated vertical. ie: 1000 meters of 50 degrees = 660m of 45 degrees.

Alaska Heliskiing - Subtract 20 degrees and cut the vertical in half. FIVE THOUSAND FUGGIN' FEET OF 60 DEGREES (Dude!) = 2,500' of 40 degrees.

Montana & Washington - accept at stated values.

California - Subtract 10 degrees, nip the vert by 1/4 and double the width of any stated couloir.

Oregon - there is no steep skiing in Oregon.

The East Coast - Overstated stats, but the conditions justify it. Accept at stated value.

Colorado - Whatever Lou said it was.

Utah - I'll take the 5th on that.

Film/Movies - cut stated angles and length in half.

http://www.telemarktalk.com/phpBB/viewtopic.php?p=36783#36783

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Accoridng to Better Skiing "The gradient needs to be more than 45 degrees to be considered steep, and from 55 to 70 degrees to be extreme. Don't try anything more than 55 degrees to start with."
The Courchevel Couloirs are quoted at 38 degrees, and I understand they are considered quite steep (never tried them) - what the hell is 55 degrees like? Shocked

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After all it is free

can someone explain therefore, why, if you angle a bit of paper at 30 degrees, it doesnt look half as steep as some of these nasty blacks you're talking about. I'm confused.

davidof, I got the Courchevel Couloir data from SnowTrip and SkiSolutions .
Better Skiing not to blame.

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Me too Bend Zinees. Probably the same phenomenon that makes slopes look easy from the bottom (or chair lift) but hell from the top.

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It's all in the mind of the beholder guys Cool

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Degrees of terror?

Concerned
Worried
Tense
Dribbling
Puckered
Unpuckered and smelly
Unpuckered and lumpy
OH f*** I’m gonna die!
OH f*** I’m gonna die but someone’s got a vid camera! (so put it behind ‘tense’)
OH f*** I’m gonna die . . . S*** that chick’s real cute! I’m a god and nothing can hurt me!

You know it makes sense.

Otherwise you'll just go on seeing the one name:

davidof, great picture. Two questions: how did you get up there, and how did you take the picture? Is there a helicopter involved? (sorry: 3 questions)
And what does YMMV stand for? And who goes round with a clinometer? (5 questions!)

A snowHead

A snowHead

I skied what was claimed to be a 50 degree slope in breckenridge (Lake Chutes), the start was pretty tough altho it mellowed out really quickly. I've got a great picture from the entry gate that'll i'll try and get posted somewhere.

What i'd like explaining is the difference between degrees and percentage, I was in Chamonix recently and one of the black runs at Brevent had a sign which said danger 75%, what does that mean in terms of steepness?

Well, the person's real but it's just a made up name, see?

WaistDeepInPow, percentage is weird. This site has some specifics, but basically, it's vertical rise divided by horizontal run. 100% is 45 degrees.

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ssh, thanks for clearing that up. Think i prefer your concise explanation to all that info on the site tho! Confused

Anyway, snowHeads is much more fun if you do.

WaistDeepInPow, I like to provide reference material--it's the scientist in me! Wink

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If (like me) you can't make sense of ssh's site, high school trignonometry will come to the rescue. To convert from degrees to percentage, bung the number into a calculator (the one in the Accessories menu of Windows will do nicely), press the Tan button and multiply by 100. To convert from percentage to degrees, divide by 100, click the Inv box and hit the Tan button.

Or make a wild guess and choose the figure that suits your story best, eg "last time I was steaming down a run above 150%..." or "my wife can't handle anything steeper than 5 degrees..."

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Bend Zinees, it's all to do with how far parts of the slope seem from your nose. If you're standing on the slope and it's 45 degrees, assuming you're six feet tall, the slope will meet your eye level only six feet away (looking uphill). This may sound a lot, but it's not and it's reasonable scarey. Add to that the fact you're probably leaning into the hill a bit to keep your edge and you'll feel the hill is almost vertical.

What's even worse though, is the other way. When you want to turn, you are going to have to get your body downhill and your weight forward. Especially when you're planting your pole. It's very hard to convince your brain to chuck yourself down what seems a steep slope. The brain doesn't mind at all if you're standing in the cable car looking up at the slope, but when you're on it, it has quite a different opinion!

After all it is free

Have to say that Better SKiing is talking cr*p. 45 degrees is very steep. I think 35 degrees is probably where steep really starts. "Don't try anything more than 55 degrees at first" or ever unless you are a real hero...

I worked a season in Courchevel and know the couloirs well. I'd say the the figures quoted are about right. I think most good skiers would say that Sous la telecabine feels pretty steep (at the top anyway) but certainly not extreme. Taken as a whole, the Grand Couloir is a steepish black run. What makes it feel different is the initial pitch which (for a few turns only) is probably 35 degrees and fairly narrow, after that it flattens out.

Oh, the other thing about the couloirs is that I still find the cat track at the top (at least when it is rutted and icy) the most intimidating bit!

J

Very interesting information. My admiration for people trying to establish the gradient scientifically, using equipment like inclinometer.

The gradient of a slope (on or off piste) seems to be psychological because as human we never descend such a steep slope without using our hands, let alone having a pair of long and slippery skis fixed to our feet. We are scared because we lack the prior experience.

While standing at the top of a major challenge, arguing about what person in his/her right mind would go down this slope then there seems to be skiers appearing from nowhere, shooting pass us, charging down the slope, twisting their bums along and disappearing as little ants in a fraction of minute while we are still searching the snow for our dropped jaws.
rolling eyes

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Jonny Jones, cheers for the high school refresher, i would have paid more attention had i known the knowledge would come in useful on the slopes... rolling eyes

Don't think i'll be able to access the Accessories menu on windows when i see one of those signs tho! Shocked

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Okay, I've dropped in almost every Lake Chute run and have to admit that some 'entries' exceed 50 degrees on the inclinometer, but this is a misnomer, as a cornice can build quickly with high winds driving the pitch to build.

Now about maintaining a Piste? Here's my remark. For the most part, slope determines the general pitch, but snowpack and ice formations can change terrain.

Ski areas are more than ski areas these days. They're ski areas and snowboard parks and all kinds of equipment sliding parks. Ski areas are also facing great advances in equipment and for that matter, the learning curve of skiers and riders alike is now shorter. I was at Breckenridge last week and saw half a dozen fairly good but so so boarders do moebius flips on sequential jumps. Times have changed.

So too is the area ride or ski potential. Steep terrain needs to exceed 50 degrees for most double black EX enthusiasts or they're bored, and there are bunches of these folks out there. There's also the little problem of the average joe double black skiier being goaded into terrain they cannot handle, and there are people taking daily falls that exceed 300 or so feet at many steep areas. Oddly enough, they're usually not the ones getting killed

Back to Piste. Okay a snow cat or for that matter a snowmobile has a vertical velocity limit. So the question seems to be, how do you groom a slope, or clear a slope that exceeds 50 degrees? In my view, that's the job of ski patrol, dynamite, and mortars. They'll settle that kind of slope down. Oh, using a shovel or two on a cornice doesn't hurt either.

I kind of like the following website for in-bound steep discussion, but there are others too that address this, including this forum. Good topic

http://www.steepchutes.com

http://www.pawprince.com/pawprince/writings/text_versions/tao_chutes.htm

http://www.allmountainskipros.com/All-Mountain-Clinics Laughing

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SummitPostr, welcome to snowHeads

- This is a 5 year old thread you have resuscitated btw...

Lots of European blacks do get pisted.

As regards angles of US double blacks. Tower 3 and Alta chutes at JH do not get to 50 degrees even on the steeper bits. There is a website which gives much better details of lengths and steepness of runs across the US - linked to from another thread about this topic here - but I cannot find it.... The proportion of US/Canadian runs which are above even 40 degrees is small.

The chief problem is that -as I understand it - except for Alaska and other wetter snow areas, snow simply does not want to stick at 50 degrees and above on anything more than tiny pitches. Cornices and drop-offs, and conditions are what - as you say - add to gnarliness.

You know it makes sense.

Since the last time I posted in this thread I have discovered the steepest "groomed" piste in Austria the "Harakiri" having a gradient of 78% or 38 degree. This piste requires the snowbasher winched by a steel cable during the grooming operation as it may be unsafe for a snowbasher to travel on such a gradient.

Ungroomed piste can have a steeper gradient. There has been some discussion about the "wall of death" or the Swiss Wall or the La Chavanette ski route between the French and Swiss side of Porte du Soleil. This ungroomed piste has about 40 degree.

Otherwise you'll just go on seeing the one name:

A snowHead

There was a black in Westendorf which had a 'beware' sign and I'm sure it was marked 80% - it runs under the Alpenrose gondola. The OH whizzed down and said it was fine. I don't know what that is in degrees.

A snowHead

Well, the person's real but it's just a made up name, see?

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Anyway, snowHeads is much more fun if you do.

The Tunnel wouldnt be so bad if groomed. The 6ft high moguls last week meant its gradient was more like 20/90 degrees as you went over the bumps. Dont think its been groomed at all lately

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It is rare for European blacks to be over 30º (the Good Ski Guide used to mention if any run in a resort was over 30º and there weren't many resorts in Europe had one - most mentioned were in the USA). For over 35º in Europe you have to go off-piste.

Domestic stairs are mostly about 75% (37º) (maximum steepness allowed for stairs in public places is 34º). Have a look down your stairs and imagine them continuing averaging that gradient for a long pitch (ie bits steeper and bits less steep). If there are moguls then the front face could be 50º or m ore but actually you never get moguls on anything over 35º.

I did the Steep and Deep Camp at Jackson Hole and the instructor agreed that none of the named chutes in-bound we did was over 35º (Corbetts entry is a jump - I'm not counting that). I was very disappointed - we had to go out of bounds by ourselves to find powder and steeper slopes - the instructors were not allowed to take us (and I gather even the guides are not allowed to take people in the back country [Granite etc] where we had the most fun and good snow - they could only guide in what they call the "Side Country").

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snowball,

Did you get a chance to do Corberts?

After all it is free

snowball, top of tower 3 is 42-45 degrees I believe. Alta 0 similar. There is data somewhere on this. I suspect your instructor was misinformed.

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I thought we did all the Alta chutes, but I'm not sure where tower 3 is - perhaps we didn't do it.
All I know is that we skied steeper slopes on the Whistler "extremely Canadian" and on our first days skiing by ourselves at Jackson than we did on the Camp which was very tame. We broke away and missed the last day of the camp to ski powder and chutes in Granite. We also did a day tour on our own beyond Granite before the camp. The people we talked to on the camp all seemed to think going out of bounds was really risky but it was just like off-piste in Europe. Our first descent into Granite on our second day (not a steep chute but just the nearest gate to the tram) we made the only tracks in powder down the whole face, while the inbounds was all hard moguls with not a turn in powder available.

I think perhaps the Camp was suffering from taking on too many people - it was huge.

DB, the inbounds was all hard moguls when I was there - Corbets was hard and rutted in a way which prevented you turning across the slope when you landed, and a sort of trench by the rock face. I was with people who had skied it before and, like me, none of them fancied it as it was. I gather one person on the camp (the nephew of one of the instructors) did ski it.

Help!!

What is the maximum gradient of a piste slope (in degree)?

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