Southern Alps

Snow highlights the Southern Alps in this satellite image of the South Island, New Zealand.
View of the Southern Alps from road.

The Southern Alps is a mountain range which runs along the western side of the South Island of New Zealand. It forms a natural dividing range along the entire length of the South Island. The term "Southern Alps" generally refers to the entire range, although separate names are given to many of the smaller ranges that form part of it.

Aoraki/Mount Cook is the highest point, 3,754 metres (12,320 ft). There are 16 other points in the range that exceed 3,000 metres in height. A large proportion of the range is protected as part of various national parks, notably the Westland National Park, Mount Aspiring National Park, and Aoraki/Mount Cook National Park. The Southern Alps contain some 360 glaciers, the largest of which - the Tasman Glacier - is 29 kilometres in length.[1]

The Southern Alps were named by Captain Cook on March 23, 1770, who described their 'prodigious height'.[2] 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'.[3]

Geologically, the Southern Alps lie along a plate boundary, part of the Pacific Ring of Fire. The Alpine Fault developed 25-30 million years ago, with the Indo-Australian Plate in the west pushing northwestward, the Pacific Plate to the east being subducted beneath it.[4] The mountains that form the Alps continue to be uplifted by tectonic pressure, causing earthquakes on the Alpine Fault, but they are eroded at approximately the same rate.

Because of its orientation perpendicular to 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 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.

References

  1. ↑ Lambert, M. (ed) (1989) Air New Zealand Almanack Wellington: New Zealand Press Association. p. 165
  2. ↑ Reed, A.W. (1975) Place names of New Zealand. Wellington: A.H. & A.W. Reed. ISBN 0-589-00933-8. p. 384.
  3. ↑ Orsman, H. and Moore, J. (eds) (1988) Heinemann Dictionary of New Zealand Quotations, Heinemann, Page 629.
  4. ↑ Kirkpatrick, R. (1999) Bateman Contemporary Atlas of New Zealand. Auckland: David Bateman. Plates 2 and 3.