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32-437: The Southern Alps ( Māori : Kā Tiritiri o te Moana ; officially Southern Alps / Kā Tiritiri o te Moana ) are a mountain range extending along much of the length of New Zealand's South Island , reaching its greatest elevations near the range's western side. The name "Southern Alps" generally refers to the entire range, although separate names are given to many of the smaller ranges that form part of it. The range includes

64-526: Is Aoraki / Mount Cook , the highest point in New Zealand at 3,724 metres (12,218 ft). The Southern Alps include sixteen other points that exceed 3,000 metres (9,800 ft) in height (see NZ mountains by height ). The mountain ranges are bisected by glacial valleys, many of which are infilled with glacial lakes on the eastern side including Lake Coleridge in the north and Lake Wakatipu in Otago in

96-572: Is a band of high white lenticular cloud that forms on the eastern side of New Zealand's South Island and which looks like an arch in an otherwise clear blue sky over the Southern Alps . It is accompanied by a strong hot northwesterly or northerly wind known as a "nor'wester". In Canterbury , where it is a well known feature, it is also called the Canterbury arch . It also occurs in Otago and Marlborough and east of mountain ranges along

128-538: Is at work while the mountains are being uplifted until the mountains are reduced to low hills and plains. The early Cenozoic uplift of the Rocky Mountains of Colorado provides an example. As the uplift was occurring some 10,000 feet (3,000 m) of mostly Mesozoic sedimentary strata were removed by erosion over the core of the mountain range and spread as sand and clays across the Great Plains to

160-478: Is frequently visible in summer across Canterbury and North Otago . The 'Nor'wester' is a foehn wind similar to the Chinook of Canada, where mountain ranges in the path of prevailing moisture laden winds force air upwards, thus cooling the air and condensing the moisture to rain, producing hot dry winds in the descending air lee of the mountains. The Southern Alps lie along a geological plate boundary , part of

192-865: The Alpide belt . The Pacific Ring of Fire includes the Andes of South America, extends through the North American Cordillera , the Aleutian Range , on through Kamchatka Peninsula , Japan , Taiwan , the Philippines , Papua New Guinea , to New Zealand . The Andes is 7,000 kilometres (4,350 mi) long and is often considered the world's longest mountain system. The Alpide belt stretches 15,000 km across southern Eurasia , from Java in Maritime Southeast Asia to

224-551: The Annamite Range . If the definition of a mountain range is stretched to include underwater mountains, then the Ocean Ridge forms the longest continuous mountain system on Earth, with a length of 65,000 kilometres (40,400 mi). The position of mountain ranges influences climate, such as rain or snow. When air masses move up and over mountains, the air cools, producing orographic precipitation (rain or snow). As

256-804: The Iberian Peninsula in Western Europe , including the ranges of the Himalayas , Karakoram , Hindu Kush , Alborz , Caucasus , and the Alps . The Himalayas contain the highest mountains in the world, including Mount Everest , which is 8,848 metres (29,029 ft) high. Mountain ranges outside these two systems include the Arctic Cordillera , Appalachians , Great Dividing Range , East Siberians , Altais , Scandinavians , Qinling , Western Ghats , Vindhyas , Byrrangas , and

288-574: The Mithrim Montes and Doom Mons on Titan, and Tenzing Montes and Hillary Montes on Pluto. Some terrestrial planets other than Earth also exhibit rocky mountain ranges, such as Maxwell Montes on Venus taller than any on Earth and Tartarus Montes on Mars . Jupiter's moon Io has mountain ranges formed from tectonic processes including the Boösaule , Dorian, Hi'iaka and Euboea Montes . Nor%27west arch The nor'west arch

320-649: The Pacific Ring of Fire , with the Pacific Plate to the southeast pushing westward and colliding with the northward-moving Indo-Australian Plate to the northwest. Over the last 45 million years, the collision has pushed up a 20 km thickness of rocks on the Pacific Plate to form the Alps, although much of this has been eroded away. Uplift has been most rapid during the last 5 million years, and

352-587: The Tasman Sea , and it is pushed up by the presence of the Southern Alps, causing it to cool rapidly. The area to the east of the divide is in the rain shadow of the Alps; much of the moisture is dumped on the West Coast , and is responsible for the temperate rainforests found there. As the air passes over the alps, the water vapour remaining becomes visible in a band of cloud over the mountains at

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384-487: The West Coast , 15,000 millimetres (590 in) close to the Main Divide, to 1,000 millimetres (39 in) 30 kilometres (19 mi) east of the Main Divide. This high precipitation aids the growth of glaciers above the snow line . Large glaciers and snowfields can be found west of or on the Main Divide, with smaller glaciers farther east (See Glaciers of New Zealand ). Because of its orientation perpendicular to

416-479: The great spotted kiwi (Apteryx haastii) , the South Island kākā (Nestor meridionalis meridionalis) , and the orange-fronted kākāriki (Cyanoramphus malherbi) . The kea can be found in the forested foothills as well as higher, colder elevations. It is the world's only alpine parrot , and was once hunted as a pest. The mountains are inaccessible and retain their natural vegetation. A large proportion of

448-577: The Alpine Fault to dip-slip motion at these subduction zones to the north creates the Marlborough Fault System , which has resulted in significant uplift in the region. In 2017 a large international team of scientists reported they had discovered beneath Whataroa , a small township on the Alpine Fault, "extreme" hydrothermal activity which "could be commercially very significant". The mountains are rich in flora with about 25% of

480-667: The Ocean". The English explorer James Cook bestowed the name Southern Alps on 23 March 1770, admiring their "prodigious height". They had previously been noted by Abel Tasman in 1642, whose description of the South Island's west coast is often translated as "a land uplifted high". Following the passage of the Ngāi Tahu Claims Settlement Act 1998 , the official name of the range was updated to Southern Alps / Kā Tiritiri o te Moana . The Southern Alps run approximately 500 km northeast to southwest. Its tallest peak

512-650: The South Island's Main Divide , which separates the water catchments of the more heavily populated eastern side of the island from those on the west coast. Politically, the Main Divide forms the boundary between the Marlborough , Canterbury and Otago regions to the southeast and the Tasman and West Coast regions to the northwest. The Māori name of the range is Kā Tiritiri o te Moana , meaning "the Mirage of

544-424: The Southern Alps in the New Zealand road network include Lewis Pass ( SH 7 ), Arthur's Pass ( SH 73 ), Haast Pass ( SH 6 ), and the road to Milford Sound ( SH 94 ). New Zealand has a humid maritime, temperate climate with the Southern Alps lying perpendicular to the prevailing westerly flow of air. Annual precipitation varies greatly across the range, from 3,000 millimetres (120 in) at

576-627: The air descends on the leeward side, it warms again (following the adiabatic lapse rate ) and is drier, having been stripped of much of its moisture. Often, a rain shadow will affect the leeward side of a range. As a consequence, large mountain ranges, such as the Andes, compartmentalize continents into distinct climate regions . Mountain ranges are constantly subjected to erosional forces which work to tear them down. The basins adjacent to an eroding mountain range are then filled with sediments that are buried and turned into sedimentary rock . Erosion

608-467: The conifer snow totara (Podocarpus nivalis) and Carex sedge grasses. Wildlife of the mountains includes the endemic rock wren (Xenicus gilviventris) . There are also a number of endemic insects adapted to these high altitudes, like flies, moths, beetles, bees, and the mountain stone wētā , which can freeze solid over winter to survive the alpine conditions. The beech forests of the lower elevations are important habitat for several birds, such as

640-586: The country's plant species being found above the treeline in alpine plant habitats and grassland with mountain beech forest at lower elevations (of the eastern side but not in Westland ). The cold windswept slopes above the treeline are covered with areas of fellfield . To the east, the Alps descend to the Canterbury-Otago tussock grasslands . Plants adapted to the alpine conditions include woody shrubs like Hebe , Dracophyllum , and Coprosma ,

672-479: The cyclonic system associated with a front gives these nor'westers their strength; they will commonly reach gale force and cause isolated damage to trees and buildings. Once every few years, a nor'wester will approach hurricane strength and cause widespread damage. The heat and lack of moisture characteristic of nor'westers play a major role in the intermittent droughts experienced by Canterbury and other regions on New Zealand's eastern coasts. The nor'wester has

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704-696: The east coast of the North Island . Closer to the Canterbury coast, some distance from the mountains of the Southern Alps, it appears as a clear area of blue above the mountains, with white cloud streaming to the east from it. The phenomenon is similar to the Chinook arch seen in the Pacific regions of the United States and Canada. The nor'west arch is a föhn cloud or a lenticular cloud . The northwesterly wind drives warm moist air from over

736-415: The east of the mountains. The nor'wester can blow at any time of year, but is less common in winter. Many of the strongest northerly and northwesterly winds blow ahead of cold fronts . A front lying across the South Island will often extend from northwest to southeast, reaching northern parts of the West Coast before it reaches corresponding areas on the east coast. The steep air pressure gradient ahead of

768-485: The east. This mass of rock was removed as the range was actively undergoing uplift. The removal of such a mass from the core of the range most likely caused further uplift as the region adjusted isostatically in response to the removed weight. Rivers are traditionally believed to be the principal cause of mountain range erosion, by cutting into bedrock and transporting sediment. Computer simulation has shown that as mountain belts change from tectonically active to inactive,

800-473: The front passes through. In mid-winter, a nor'wester is often followed by a brief but intense cold snap, frequently bringing thunder, hail, or rain and sometimes snow which may settle to sea level. The nor'west arch can be seen as far north as Amberley and as far south as Central Otago , but it is at its most prominent on the Canterbury Plains , due to the flat and low-lying nature of the land to

832-629: The mountains continue to be raised today by tectonic pressure, causing earthquakes on the Alpine Fault and other nearby faults. Despite the substantial uplift, most of the relative motion along the Alpine Fault is transverse , not vertical . However, significant dip-slip occurs on the plate boundary to the north and east of the North Island, in the Hikurangi Trough and Kermadec Trench . The transfer of motion from strike-slip on

864-481: The prevailing westerly winds, the range creates excellent wave soaring conditions for glider pilots. The town of Omarama , in the lee of the mountains, has gained an international reputation for its gliding conditions. The prevailing westerlies also create a weather pattern known as the Nor'west arch , in which moist air is pushed up over the mountains, forming an arch of cloud in an otherwise blue sky. This weather pattern

896-768: The range is well protected by national parks—notably the Westland Tai Poutini National Park , Mount Aspiring National Park , and Aoraki / Mount Cook National Park —or by protected areas such as Lake Sumner Forest Park . Indigenous plant life is affected by introduced animals such as red deer ( Cervus elaphus ), chamois ( Rupicapra rupicapra ), and Himalayan tahr ( Hemitragus jemlahicus ), all of which have at times been targeted for culling. Likewise, native birds and reptiles are vulnerable to introduced predators. Mountain range Mountain ranges are usually segmented by highlands or mountain passes and valleys . Individual mountains within

928-627: The rate of erosion drops because there are fewer abrasive particles in the water and fewer landslides. Mountains on other planets and natural satellites of the Solar System, including the Moon , are often isolated and formed mainly by processes such as impacts, though there are examples of mountain ranges (or "Montes") somewhat similar to those on Earth. Saturn 's moon Titan and Pluto , in particular, exhibit large mountain ranges in chains composed mainly of ices rather than rock. Examples include

960-471: The same mountain range do not necessarily have the same geologic structure or petrology . They may be a mix of different orogenic expressions and terranes , for example thrust sheets , uplifted blocks , fold mountains, and volcanic landforms resulting in a variety of rock types . Most geologically young mountain ranges on the Earth's land surface are associated with either the Pacific Ring of Fire or

992-518: The south. According to an inventory conducted in the late 1970s, the Southern Alps contained over 3,000 glaciers larger than one hectare, the longest of which – the Tasman Glacier – is 23.5 kilometres (14.6 mi) in length which has retreated from a recent maximum of 29 kilometres (18 mi) in the 1960s. Settlements include Maruia Springs, a spa near Lewis Pass , the town of Arthur's Pass , and Mount Cook Village . Major crossings of

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1024-435: The top of each wave of air. From the perspective of a viewer on the eastern side, this appears as an 'arch' of cloud. The standing wave or arch is caused by the moisture condensing and becoming visible towards the top of the wave and then evaporating again as the air descends to the trough of the wave. Nor'westers caused by cold fronts will often change within a day or two to a cool southerly wind accompanied by rain showers, as

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