An arête ( ) is a narrow ridge of

rock Rock most often refers to: * Rock (geology), a naturally occurring solid aggregate of minerals or mineraloids * Rock music, a genre of popular music Rock or Rocks may also refer to: Places United Kingdom * Rock, Caerphilly, a location in Wales ...

which separates two valleys. It is typically formed when two

glacier A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as ...

s erode parallel

U-shaped valley U-shaped valleys, also called trough valleys or glacial troughs, are formed by the process of glaciation. They are characteristic of mountain glaciation in particular. They have a characteristic U shape in cross-section, with steep, straight s ...

s. Arêtes can also form when two glacial

cirques A (; from the Latin word ') is an amphitheatre-like valley formed by glacial erosion. Alternative names for this landform are corrie (from Scottish Gaelic , meaning a pot or cauldron) and (; ). A cirque may also be a similarly shaped landform ...

erode headwards towards one another, although frequently this results in a saddle-shaped pass, called a col. The edge is then sharpened by freeze-thaw weathering, and the slope on either side of the arête steepened through

mass wasting Mass wasting, also known as mass movement, is a general term for the movement of rock or soil down slopes under the force of gravity. It differs from other processes of erosion in that the debris transported by mass wasting is not entrained in ...

events and the erosion of exposed, unstable rock. The word ''arête'' () is actually French for "edge" or "ridge"; similar features in the

Alps The Alps () ; german: Alpen ; it, Alpi ; rm, Alps ; sl, Alpe . are the highest and most extensive mountain range system that lies entirely in Europe, stretching approximately across seven Alpine countries (from west to east): France, Sw ...

are often described with the

German German(s) may refer to: * Germany (of or related to) ** Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ge ...

equivalent term ''Grat''. Where three or more cirques meet, a

pyramidal peak A pyramidal peak, sometimes called a glacial horn in extreme cases, is an angular, sharply pointed mountain peak which results from the cirque erosion due to multiple glaciers diverging from a central point. Pyramidal peaks are often examples o ...

is created.

Cleaver

Clouds Rest with Half Dome in the background

A ''cleaver'' is a type of arête that separates a unified flow of glacial

ice Ice is water frozen into a solid state, typically forming at or below temperatures of 0 degrees Celsius or Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaq ...

from its uphill side into two glaciers flanking, and flowing parallel to, the ridge. ''Cleaver'' gets its name from the way it resembles a meat cleaver slicing meat into two parts. A cleaver may be thought of as analogous to an

island An island (or isle) is an isolated piece of habitat that is surrounded by a dramatically different habitat, such as water. Very small islands such as emergent land features on atolls can be called islets, skerries, cays or keys. An island ...

in a

river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...

. A common situation has the two flanking glaciers melting to their respective ends before their courses can bring them back together; the exceedingly rare analogy is a situation of the two branches of a river drying up, before the downstream tip of the island, by evaporation or absorption into the ground. The location of a cleaver is often an important factor in the choice among routes for glacier flow. For example, following a cleaver up or down a mountain may avoid travelling on or under an unstable glacial, snow, or rock area. This is usually the case on those summer routes to the summit whose lower portions are on the south face of

Mount Rainier Mount Rainier (), indigenously known as Tahoma, Tacoma, Tacobet, or təqʷubəʔ, is a large active stratovolcano in the Cascade Range of the Pacific Northwest, located in Mount Rainier National Park about south-southeast of Seattle. With a s ...

: climbers traverse the ‘flats’ of ''Ingraham Glacier'', but ascend ''Disappointment Cleaver'' and follow its ridgeline rather than ascending the

headwall In physical geography and geology the headwall of a glacial cirque is its highest cliff. The term has been more broadly used to describe similar geomorphic features of non-glacial origin consisting of a concave depression with convergent slopes ty ...

either of that glacier or (on the other side of the cleaver) of

Emmons Glacier Emmons Glacier is on the northeast flank of Mount Rainier, in Washington. At , it has the largest surface area of any glacier in the contiguous United States. The glacier was named after the geologist Samuel Franklin Emmons after his involvement i ...

Crib Goch, Snowdonia, Wales - August 2007

Examples

Notable examples of arêtes include: *

Beenkeragh Ridge Beenkeragh or Benkeeragh () is the second-highest peak in Ireland, at , on both the Arderin and Vandeleur-Lynam lists. It is part of the MacGillycuddy's Reeks range in County Kerry. Beenkeragh also gives its name the infamous ''Beenkeragh Ridge ...

MacGillycuddy's Reeks , photo=MacGuillycuddy's Reeks.jpg , photo_caption= , country=Ireland , country1= , location = County Kerry , region = Munster , region_type = Provinces of Ireland , parent= , border= , length_km=19 , length_orientation=East–West ...

, County Kerry, Ireland. * The Carn Mor Dearg arête on to

Ben Nevis Ben Nevis ( ; gd, Beinn Nibheis ) is the highest mountain in Scotland Scotland (, ) is a Countries of the United Kingdom, country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland ...

, Scotland *

Clouds Rest Clouds Rest is a mountain in Yosemite National Park east northeast of Yosemite Village, California. Although there are many peaks in the park having far greater elevation, the proximity of Clouds Rest to the valley gives it a very high degree of ...

, in the

Sierra Nevada The Sierra Nevada () is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primarily ...

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

* Crib Goch, in

Snowdonia National Park Snowdonia or Eryri (), is a mountainous region in northwestern Wales and a national park of in area. It was the first to be designated of the three national parks in Wales, in 1951. Name and extent It was a commonly held belief that the nam ...

, Wales * The

Garden Wall The Garden Wall is a steep alpine area within Glacier National Park well known during the summer months to be heavily covered in dozens of species of flowering plants and shrubs. Located along the west side of the Continental divide and extending ...

, in Glacier National Park,

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbi ...

(image to right) *

Half Dome Half Dome is a granite dome at the eastern end of Yosemite Valley in Yosemite National Park, California. It is a well-known rock formation in the park, named for its distinct shape. One side is a sheer face while the other three sides are smooth ...

, in

Yosemite National Park Yosemite National Park ( ) is an American national park in California, surrounded on the southeast by Sierra National Forest and on the northwest by Stanislaus National Forest. The park is managed by the National Park Service and covers an ar ...

, California * Knife Edge, in

Baxter State Park Baxter State Park is a large wilderness area permanently preserved as a state park in Northeast Piscataquis, Piscataquis County in north-central Maine, United States. It is in the North Maine Woods region and borders the Katahdin Woods and Wate ...

, Maine *

Koncheto Koncheto ( , ) is a name given to a knife-edge ridge in the Pirin Mountains in Bulgaria, at an elevation of approximately 2,810 metres, between the peaks Banski Suhodol (2,884 meters) and Kutelo (2,908 metres). There are steep slopes on either ...

Pirin , photo=Pirin-mountains-Bansko.jpg , photo_caption=Pirin scenery in winter , country= Bulgaria, , parent= , geology= granite, gneiss, marble, limestone , area_km2=2585 , range_coordinates = , length_km=80 , length_orientation= north-s ...

mountain,

Bulgaria Bulgaria (; bg, България, Bǎlgariya), officially the Republic of Bulgaria,, ) is a country in Southeast Europe. It is situated on the eastern flank of the Balkans, and is bordered by Romania to the north, Serbia and North Macedon ...

Mazeno Ridge The Mazeno Ridge is an arête, a long narrow ridge, and part of the Nanga Parbat massif in Gilgit–Baltistan, Pakistan, in the Himalayan range. The ridge is the longest of any ridge on the eight-thousand-metre peaks in the Himalayas. A serie ...

Gilgit-Baltistan Gilgit-Baltistan (; ), formerly known as the Northern Areas, is a region administered by Pakistan as an administrative territory, and constituting the northern portion of the larger Kashmir region which has been the subject of a dispute bet ...

, Pakistan *

The Minarets The Minarets are a series of jagged peaks located in the Ritter Range, a sub-range of the Sierra Nevada in the state of California. They are easily viewed from Minaret Summit, which is accessible by auto. Collectively, they form an arête, and a ...

, in the Sierra Nevada, California *

The Sawtooth The Sawtooth is a jagged arête joining Mount Bierstadt to (eventually) Mount Evans in the Front Range of central Colorado.Randy Jacobs and Robert M. OrmesGuide to the Colorado Mountains Colorado Mountain Club Press, 2000; page 74. The three poin ...

, in the

Southern Rocky Mountains The Southern Rocky Mountains are a major subregion of the Rocky Mountains of North America located in the southeastern portion of the U.S. state of Wyoming, the central and western portions of Colorado, the northern portion of New Mexico, and ex ...

* Strazhite (The guardians),

mountain,

Striding Edge Helvellyn (; possible meaning: ''pale yellow moorland'') is a mountain in the English Lake District, the highest point of the Helvellyn range, a north–south line of mountains to the north of Ambleside, between the lakes of Thirlmere and Ulls ...

in the English

Lake District The Lake District, also known as the Lakes or Lakeland, is a mountainous region in North West England. A popular holiday destination, it is famous for its lakes, forests, and mountains (or ''fells''), and its associations with William Wordswor ...

* Trionite (The Saws),

Rila Rila ( bg, Рила, ) is the highest mountain range of Bulgaria, the Balkans, Balkan Peninsula and Southeast Europe. It is situated in southwestern Bulgaria and forms part of the Rila–Rhodope Mountains, Rhodope Massif. The highest summit is Mus ...

mountain,

References

Sources

External links

Diagram

{{DEFAULTSORT:Arete Mountaineering Glacial erosion landforms Ridges Oronyms

Cleaver

Examples

See also

References

Sources

External links