Tasman Glacier

Tasman Glacier
Upper half of the Tasman Glacier
Type	Mountain glacier
Location	New Zealand
Coordinates	43°37′S 170°12′E / 43.617°S 170.200°E / -43.617; 170.200Coordinates: 43°37′S 170°12′E / 43.617°S 170.200°E / -43.617; 170.200
Area	101 km2 (39 sq mi)
Length	23.5 km (14.6 mi)
Thickness	600 m (2,000 ft)
Terminus	Lake Tasman
Status	Retreating

The Tasman Glacier is the largest of several glaciers which flow south and east towards the Mackenzie Basin from the Southern Alps in New Zealand's South Island. It is New Zealand's longest glacier.

At 23.5 kilometres (14.6 mi) in length, Tasman Glacier is still New Zealand's longest glacier, although it has shrunk considerably from the 1990s onwards. It is as much as 4 kilometres (2.5 mi) wide and 600 metres (2,000 ft) thick, and lies entirely within the borders of Aoraki/Mount Cook National Park. The glacier covers an area of 101 square kilometres (39 sq mi) and starts at a height of 3,000 metres (9,800 ft) above sea level. Snowfall during the winter and spring seasons accumulates to 50 metres (160 ft). After the summer melt, 7 metres (23 ft) remains.

The Tasman flows south from the southern slopes of the Minarets peak, along the eastern flank of New Zealand's two highest mountains, Mount Tasman and its higher southern neighbour Aoraki / Mount Cook.

Although its upper reaches are snow-covered, rocks carried by the glacier are exposed by ablation along its course, and the lower glacier is entirely rock-covered. The rock cover helps insulate the ice from the sunlight and slows down the melting process. Tributaries in the lower parts are the Rudolf Glacier, Forrest Ross Glacier, Kaufmann Glacier, Haast Glacier, Hochstetter Glacier, and Ball Glacier.

The glacier is almost met near its end by the meltwater of the Murchison Glacier, which approaches from the northeast before turning to flow beside the Tasman Glacier outside the moraine wall. The waters from both these glaciers pool at the end of the glacier in Lake Tasman, before flowing south to join the outflow from the nearby Hooker and Mueller Glaciers in the wide valley of the Tasman River, whose braided streams flow south into Lake Pukaki. They eventually flow into the Waitaki River and to the Pacific Ocean north of Oamaru.