| Mountain Prominence Definition Mountain Prominence is a measure of how distinct a mountain is from the next higher mountain up the ridge. Last Reviewed: 2010.09.01 "Mountain Prominence" is a measure of how distinct and separate a mountain is from the closest higher mountain up the ridge. A low prominence mountain is just a bump on the ridge of its parent. For example, the prominence of Bodyguard Peak is only 40m, even though its height is an impressive 3316 meters. The prominence tells you that it is really just a bump on a ridge leading to Mount Waddington, height 4019m. Compare that with Mount Tiedemann which is separated from the higher Mount Waddington by a 848m drop. The prominence of Tiedemann is 848m. It is truly a separate peak. You would have to drop 848m before beginning to go up Waddington. So now you know why we bother to measure prominence - otherwise, if you look only at height, you can't tell how separate the mountain reall is.
Prominence is NOT a measure of how hard the peak is to climb, and a low prominence peak might be a quite difficult climb. It is strictly a numerical calculation from the topo maps, and everyone would get the same answer. It is not a subjective number. Note that prominence is NOT just the drop from the steepest face of the mountain to the valley below. Another term for prominence is "autonomous height". As in "the autonomous height of Resplendant mountain is only 483m, the rest of its height is regarded as the height of Mount Robson. "Autonomous" means "belonging uniquely to that mountain". It is the height of the mountain above its "base contour". It is how far you have to drop before you start going up something higher. The low point on the ridge between the two mountains is called the "key saddle". We use the term "line parent" for the first peak that is higher when traversing the prominence line. For example, consider Mount Robson (3954m) and nearby Resplendent Mountain (3408m). The "prominence" of Resplendent mountain is 483m above the Resplendent-Robson col. This "key saddle" is the lowest point on the ridge which connects Resplendent to Robson, and thus determines the prominence of the lower peak. The prominence of Mount Robson itself is more difficult to visualize, because the "higher peak" turns out to be Gannett Peak in Wyoming. The low point on the connecting ridge is Yellowhead pass (1130m). Thus the prominence of Mount Robson is 2824m above Yellowhead pass. In order to prove the prominence of a peak, you usually need to identify one or two possible "parent peaks" and then eliminate all but one of them by comparing the lowest point on their connecting ridges. This is usually pretty quick, because one is usually much lower. At this point you have the correct "promline". You must then establish that you have the right saddle. This is often where a mistake can be made, because there are often several areas that might have a slightly lower pass. For example, when considering Mount Robson, there are two possible promlines - one going west to Mount Waddington, and one going south to Gannett Peak. Step 1 is easy. The promline to Waddington can be eliminated because Summit Lake (Prince George) (710m) is much lower than Crowsnest Pass (1358m). Step 2 is a bit harder, because we have to trace the entire promline to establish that there is no lower pass across the divide before Gannett Peak. Of course it is always possible that when doing a detailed scan of the selected promline, you suddenly find a pass that is lower than the lowest pass on the first rejected promline. Prominence is used to provide a non-subjective definition of what constitutes a separate peak. It is used to come up with lists of peaks. The Canadian Mountain Encyclopedia contains the prominence of more than 10,000 mountains in North America. These prominences have been used to divide North America into "promience regions". MINIMAL PROMINENCE GLOSSARY The subject of determining prominences can be completely discussed with the following minimal set of terms: (See also Terminology for Determining Distant Prominences. Autonomous Height or Topographic Prominence: As in "The Autonomous height of Resplendant mountain is only the height that it rises above the col that connects it to Mount Robson." The vertical height of a mountain that can be said to belong totally to that mountain. That is, the height above the lowest contour that surrounds the peak and no higher peak. See "base contour". Line Parent: As in "The line parent for Mount Robson is Gannett Peak, not Elbert." Definition: The parent peak is the first higher peak that you come to on the prominence walk. It must be over 300m of prominence. This rule eliminates the possibility of obscure subpeaks suddenly becoming the parent peak of some great peak. Key Saddle: The lowest point on the ridge which connects a peak to a higher peak. Eg: The key saddle for Mount Robson is Yellowhead Pass, because it is the lowest point on the long ridge that eventually climbs to Francs Peak in Wyoming. Promline: As in: "The promline of Mount Columbia goes south along the continental divide, through Crowsnest pass, and then up to the higher Gannett Peak. The promline does not go north to Mount Robson, because Yellowhead pass is lower than Crowsnest Pass." Definition: The promline is the crest of the highest ridge which connects a mountain to its higher mountain. Summary: The main purpose of this document was to provide a minimal set of definitions sufficient to describe and explain how a mountain's prominence can be calculated and proved. I did a two part glossary: first introducing each term in chronological order, and second, listing them alphabetically. I think this is the best way to provide a subject specific glossary, because without the chronological introduction, the "dictionary" just doesn't make sense, because everything refers to everything else. In this prominence glossary, I deliberately stayed away from extra terms such as subpeak, parent peak, and lineage, because they are not necessary for the most minimal discussion. Some of those terms are introduced as separate subjects. Appendicies |