World Library  
Flag as Inappropriate
Email this Article

Mountain pass

Article Id: WHEBN0000374673
Reproduction Date:

Title: Mountain pass  
Author: World Heritage Encyclopedia
Language: English
Subject: Ukok Plateau, List of landforms, Paso de Jama, Lilpela Pass, Mamuil Malal Pass
Collection: Montane Ecology, Mountain Passes, Slope Landforms
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Mountain pass

The saddle between Mount Washington and Mount Clay in New Hampshire, USA; the mountain pass crosses left-right in the photo.
Idealized mountain pass represented as the green line; the saddle point is in red.

A mountain pass is a route through a mountain range or over a ridge. If following the lowest possible route, a pass is locally the highest point on that route. Since many of the world's mountain ranges have presented formidable barriers to travel, passes have been important since before recorded history, and have played a key role in trade, war, and migration. At lower elevations it may be called a hill pass.

Contents

  • Overview 1
  • Synonyms 2
  • Around the world 3
  • Gallery 4
  • See also 5
  • References 6
  • External links 7

Overview

A mountain pass as it appears on a contour map: Bwlch Maesgwm in Snowdonia, north Wales (, height contours from SRTM data).

Mountain passes make use of a gap, saddle or col (also sometimes a notch, the low point in a ridge). A topographic saddle is analogous to the mathematical concept of a saddle surface, with a saddle point marking the highest point between two valleys and the lowest point along a ridge.[1][2] On a topographic map, passes are characterized by contour lines with an hourglass shape, which indicates a low spot between two higher points.[3]

Passes are often found just above the source of a river, constituting a drainage divide. A pass may be very short, consisting of steep slopes to the top of the pass, or may be a valley many kilometres long, whose highest point might only be identifiable by surveying.

Roads have long been built, and more recently railways, through passes. Some high and rugged passes may have tunnels bored underneath to allow faster traffic flow throughout the year.

The top of a pass is frequently the only flat ground in the area, a high vantage point, so it is sometimes a preferred site for buildings. If a national border follows a mountain range, a pass over the mountains is typically on the border, and there may be a border control or customs station, and possibly a military post as well. For instance Argentina and Chile share the world's third longest international border, 5,300 kilometres (3,300 mi) long. The border runs north-south along the Andes mountains, with a total of 42 mountain passes.[4][5] On a road over a pass, it is customary to have a small roadside sign giving the name of the pass and its elevation above mean sea level.

As well as offering relatively easy travel between valleys, passes also provide a route between two mountain tops with a minimum of descent. As a result, it is common for tracks to meet at a pass; this often makes them convenient routes even when travelling between a summit and the valley floor. Passes traditionally were places for trade routes, communications, cultural exchange, military expeditions etc. A typical example is the Brenner pass in the Alps.

Some mountain passes above the tree line have problems with snow drift in the winter. This might be alleviated by building the road a few meters above the ground, which will make snow blow off the road.

Synonyms

There are many words for pass in the English-speaking world. In the United States, pass is very common in the West, the word gap is common in the southern Appalachians, notch in parts of New England, and saddle in northern Idaho.[6] Scotland has the Gaelic term bealach (anglicised "Balloch"), while Wales has the similar bwlch (both being British Celtic languages). In the Lake District of north west England, the term hause is often used, although the term pass is also common—one distinction is that a pass can refer to a route, as well as the highest part thereof, while a hause is simply that highest part, often flattened somewhat into a high level plateau.

Around the world

There are thousands of named passes around the world, some of which are well-known, such as the Great St. Bernard Pass at 2,473 metres (8,114 ft) in the Alps, the Khyber Pass at 1,027 metres (3,369 ft) between Afghanistan and Pakistan, and the Khardung La at 5,359 metres (17,582 ft) in Jammu and Kashmir, India. The roads at Mana Pass at 5,610 metres (18,410 ft) and Marsimik La at 5,582 metres (18,314 ft), on and near the China-India border respectively, appear to be world's two highest motorable passes.

Gallery

See also

References

  1. ^
  2. ^
  3. ^
  4. ^
  5. ^
  6. ^ Map showing "saddle" names in Idaho

External links

Media related to at Wikimedia Commons

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from Hawaii eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.