Hi all,
I've been thinking a lot about prominence lately, and how we measure it. I feel like the ways we measure it now aren't very satisfying... a mountain can look really prominent from most directions, but have one nearby peak that really reduces its prominence.

So, a couple questions:

Can you think of good examples of mountains that look really prominent from one angle, but not from another? I'm thinking a mountain on the edge of a big range or something like that. The best example I can think of right now the the Mt Bowlen in Banff - really prominent from many angles, but right near Mount Little so doesn't have much prominence in our metrics.

Do you think the ways that people measure prominence right now are any good?

It's just a technical thing with the definition of "prominence" when it comes to mountains. They describe mountain prominence as the elevation difference between a peak and the lowest contour that encircles it and no higher summit. In other words it's "prominence" is the amount of elevation you must descend in order to start climbing a higher summit.

Contrast this to the Webster definition of prominence which is the state of being important, well-known, or noticeable. It's this second definition you are thinking of and i would agree on some level. Some mountains may look really impressive or "prominent" from a certain angle but only have a small amount of prominence in terms of elevation.

One example I can think of is The Eiger. The north face of The Eiger is extremely prominent in Webster terms but only has 1,168' (356m) of elevation prominence. Little Tahoma on the shoulder of Mt. Rainier could be another example. It can look impressive in some pictures but with just over 800 feet to it's saddle with Rainier it doesn't have much prominence in terms of elevation. I'm sure there are many more examples.

awilsondc wrote:It's just a technical thing with the definition of "prominence" when it comes to mountains. They describe mountain prominence as the elevation difference between a peak and the lowest contour that encircles it and no higher summit. In other words it's "prominence" is the amount of elevation you must descend in order to start climbing a higher summit.

Exactly. And while this may seam like just a technicality, this means that there simply is no such thing as "Prominent from one angle".

That said, in the European Alps there are lots of examples of subsidiary peaks that have their own summit cross and their own name. The official list of Alpine 4000-ers by the UIAA, which counts 82 summits, is the one that many European mountaineers go by when setting themselves the goal of bagging all 4000-ers in the Alps. At the top of the list is Mont Blanc, and obviously there is no discussion whether it belongs up there. But the second one, Mont Blanc de Courmayeur, only has 18 m of prominence! In fact, more than 30 summits on the list have prominence less than 100 m. If you look deeper into how this list has come about, you'll learn that prominence is just one of the factors taken into account.

Now, Mont Blanc de Courmayeur is an interesting peak for several reasons. One thing is that Mont Blanc de Courmayeur is the highest point visible from the nearby Italian village of Courmayeur. In fact, this is the origin of a long lasting (though friendly) border dispute between France and Italy: an old treaty (signed long before modern day Italy came into existence) defined the local border to run over the highest point, but left room for interpretation as to whether this should be the real highest point, or only the highest point that could be seen from Courmayeur.


MB de Courmayeur from the Italian side

There are no real economical benefits to be gained, and the two countries are in no hurry at all to resolve the issue. For most practical purposes it simply doesn't matter. I imagine that the occasional meetings are friendly reunions, all expenses paid, where the officials have some nice food and wine and enjoy the spectacular scenery, and the only thing to show for it is a date for the next meeting. But if you're into climbing country high points, it's a bit different: depending on where the border actually is, the Italian high point is either Mont Blanc itself or Mont Blanc de Courmayeur. And It also matters if you want to camp or bivvy while climbing Mont Blanc itself: the French have issued strict local laws against that, and are actively policing the mountain. They'll send you packing if they catch you. I don't know what they do if they only discover you the next morning, but I guess they'll issue a big fine.

Now, since the official French point of view is that Mont Blanc de Courmayeur is the border, they claim the whole summit of Mont Blanc for themselves. Officially, the Italians disagree. A few years ago, bivvying just on the south side of the summit, which is in disputed territory, I was kinda hoping to get such a fine, so I could argue that the French didn't have jurisdiction because I was in Italy. I doubt if a French court would see it my way, so it might have to go all the way to the European high court. To be honest, I'm not sure if I would be interested enough to take it that far. I mean, I don't really care where the border will be, I just wanted to be allowed to bivvy up there. And though I like to have the freedom to camp and bivvy high up in the mountains, Mont Blanc is so busy that I understand the French ban on camping and bivvying. Still, I liked to think about it the fuss I might cause, imagining bureaucrats getting all worked up about it.

In other words it's "prominence" is the amount of elevation you must descend in order to start climbing a higher summit.

That's elevation prominence and is a relatively new term/definition. Prominent mountains before elevation prominence came into play meant visually dominant.

There are plenty of mountains that fit this definition.

Lone Eagle Peak in Colorado is a good example:



From the other side, the peak is barely a rocky bump at the end of the ridge. The summit in the first photo is the lower on the right:

Prominence is well-defined in that there is no arbitrariness nor room for subjectivity in its calculation. Only the accuracy of the maps plays into the accuracy of the prominence figure. Since most saddle elevations are not provided (and in many cases, summit elevations aren't either), prominence figures will have a small range, but the concept is well-grounded.

I could argue that a mountain's elevation is even a less well-defined measurement, since it depends on a presumed "sea level" which could theoretically change, and is itself just a mathematical ideal based on someone's latest geoid. In other words, if the seas rose twenty feet overnight, all mountain elevations would drop twenty feet, but their prominences would not change.

There will always be a few peaks that seem to "not fit" these, or any, definitions. For example, highpoints of sprawling plateaus will have high prominence figures, even though the HP may be in a flat area, the nearest cliffs miles away. Kaibab Plateau's HP in northern Arizona has an elevation of 9,200 feet, a prominence of 3,600 feet, yet standing at the HP, which is flat and forested, neither figure "feels" right. But this is a notable exception. Anybody into "spire" measurements?

Elevation alone never tells the whole story. Many 14er peaks in Colorado rise from an elevated plateau so that some of these peaks have prominence figures usually in the 1,000-2,000 foot range, or even in the mere hundreds of feet, whereas peaks with lower elevations in the deserts may rise to just 8,000 or 9,000 feet, but have proms over 5,000 feet. The post above regarding the low prom figures for some of the peaks on the European Alps' 4,000-m list is a good example. I'd like to see mapmakers show two figures for the big peaks, elevation/prominence. That would be interesting!

Before computers, the only way to determine a peak's prominence was to carefully trace its lower contours on a map until finding that magical lowest one ... which is impossible if you're trying to do that for a peak such as Mt Elbert, whose lowest contour stretches into Nevada somewhere, if I am not mistaken. Thus, prominence in its early days was generally discussed for smaller summit bumps whose proms could be figured quickly. For larger peaks, there was no compelling reason to do this since they were obviously "prominent" already.

Anyway, back to the original post: Blue Peak in eastern Arizona is a bump along the Mogollon Rim. Its slopes on the south, east and part of the north drop over 2,000 feet, but it is attached to the Colorado Plateau and has just about 500 feet of prominence. From the south, it looks like quite a peak. From the north and west, it's just a little bump.

Prominence is well-defined in that there is no arbitrariness nor room for subjectivity in its calculation.

A prominent mountain is simply one that is highly visible and dominant and has nothing to do with elevation prominence. It has been like that for a very long time. The "prominence" you are talking of is a much new invention and used to be called "saddle rise".

Elevation prominence is a new term that became trendy when peakbagging, highpointing, and peak list really took off. It would help if it were referred to as elevation prominence to avoid confusion, but few tack on the word "elevation" and it is unlikely to be changed. I guess it really doesn't need to be added though, since the elevation is usually mentioned anyway, making the term redundant. For example, people just say Peak A has X feet of prominence. Personally, I miss the term saddle rise. It was a much better term.