Southern Alps

Lake Wanaka, in Otago, in New Zealand's South Island, with the hills of the Southern Alps in the background. This area, on the edge of Mount Aspiring National Park, is popular for walking, skiing, and other outdoor activities.

The Southern Alps run along the western spine of New Zealand's South Island. They were formed by a vertical movement of the Earth's crust along the Alpine fault line. The western slopes have very high rainfall, and to the east, the plains of Canterbury are comparatively dry.

Range of mountains running the entire length of South Island, New Zealand. They are forested to the west, with scanty scrub to the east. The highest peaks are Aoraki, 3,764 m/12,349 ft, and Mount Tasman 3,498m/11,476 ft. Scenic features include gorges, glaciers, lakes, and waterfalls. Among its lakes are those at the southern end of the range: Manapouri, Te Anau, and the largest, Wakatipu, 83 km/52 mi long, which lies about 300 m/1,000 ft above sea level and has a depth of 378 m/1,242 ft. The Fiordland National Park also lies in the south of the range.

Physical The Southern Alps run 325 km/202 mi southwards from Arthur's Pass down the west side of the island. The rock is largely a sandstone feldspar combination called greywacke. Sixteen mountains rise above 3,000 m/9,842 ft, all near the centre of the range. The range is much more heavily glaciated than the European Alps. The Tasman glacier, on the east side of Aoraki, is 29 km/18 mi long and more than 1.5 km/0.9 mi wide. The Franz Josef glacier, on the west side, although much shorter, is fed so heavily from its upper snowfields that it flows to within 180 m/590 ft of the sea. There are no subalpine passes across the central sector of the main divide. The lowest is Copland Pass, 2,118 m/6,949 ft, between Hooker and Copland valleys.

Weather The weather of the Southern Alps is notoriously unstable. The range lies just 32 km/20 mi from the Tasman Sea, which brings heavy northwesterly storms to the main ridge. These warm, wet winds deposit their moisture on the high peaks and lesser ranges eastwards, but are dry when they cross the Canterbury Plains. They seldom deposit snow below 2,440 m/8,000 ft. Good weather comes with the cold southerly winds, and these, if prolonged, deposit snow down to 1,220 m/4,000 ft. The summer climbing season extends from mid-November to early April. February and March are reckoned to be the least unsettled months. Winter weather is much better than summer, making skiing a popular sport.