In the North Island there are seven small glaciers on the slopes of Mount Ruapehu, an active volcano (9,175 ft). Their size varies, but they are usually less than a mile in length and descend to about 7,000 ft above sea level. During the winter ski-ing period the Whakapapa Glaciers, near the Chateau Tongariro, are visited by several thousand people each week.
In the Southern Alps more than 360 glaciers have been named; they occur between 43° and 45 South latitude, and have a total area of 330 sq. miles. The major ones are located in the area around Mount Cook, the highest mountain in New Zealand (12,349 ft). Draining to the eastern side of the Divide, into the Waitaki River system, are the following glaciers: Godley (6.5 miles long), Hooker (6.5 miles long), Mueller (8 miles long), Murchison (9 miles long), and Tasman (17.5 miles long), their total area being 91 sq. miles. The two largest glaciers draining to the western side of the Southern Alps are the Franz Josef (7 miles long), and the Fox (8.5 miles long); their total area is 16.5 sq. miles.
Other glaciers lie north of the Mount Cook region, in the Rakaia-Rangitata River systems, the largest being the Ramsay and Lyell in the Rakaia catchment area. A further group is centred around Mount Aspiring (9,957 ft), 100 miles south-west of Mount Cook. The largest, the Bonar, Volta, and Therma, rise on the slopes of Mount Aspiring itself, and many smaller glaciers are clustered around the headwaters of the Arawata, Matukituki, Dart, and Hollyford Rivers. The eastern glaciers have a fairly gentle gradient and descend to between 2,500 and 3,500 ft above sea level; the western glaciers are much steeper and their terminals are as low as 1,000 ft above sea level, well down into the thick rain forests.
Glacier-movement measurements were first made in the Mount Cook region in 1889 by T. N. Brodrick . Rough estimates made by A. P. Harper of surface speeds of the Franz Josef Glacier in 1894 indicate very high rates of flow of 100 to 200 in. a day up to 2 miles from the terminus. Rates on the Tasman Glacier vary, being only about 20 in. a day from a point 7 miles up stream from the terminal. The glaciers are fed by snow brought to the Southern Alps by the prevailing winds off the Tasman Sea; total yearly snowfalls at the higher elevations (6,000–8,000 ft) vary from 10 to 20ft. The steeper West Coast glaciers have little moraine carried on their surface and have shown a marked terminal retreat in the last 10 years. The Franz Josef Glacier terminal, for example, has retreated three-quarters of a mile. The large glaciers on the eastern side of the Southern Alps are mantled with moraines, and lower parts of the glaciers have been reduced in thickness by up to 200 ft, with some terminal retreat.
In 1861 Julius von Haast , Provincial Geologist of Canterbury, with Andrew Sinclair , Colonial Secretary, began the exploration of the Rangitata Valley glaciers. (Sinclair was later drowned while crossing the Rangitata River.) During the following year Haast, with A. D. Dobson , extended the survey to the Godley Valley and, later, to the Tasman, Hooker, and Mueller Glaciers.
The Murchison Glacier was viewed from the Mount Cook Range and the explorers then visited the Dobson and Hopkins Valleys. Haast also visited and named the Franz Josef Glacier; other West Coast glaciers were discovered, during the same period, by gold miners. Few records have been kept, but it is known that the La Perouse and Copland Glaciers were visited. During 1863 James Hector sighted the glaciers in the Mount Aspiring area when he explored the west branch of the Matukituki River and crossed to the Waipara and Arawata Rivers. In 1876, S. H. Cox and A. McKay compiled a geological map of the West Coast which showed the position of the Franz Josef and Fox Glaciers. Other famous explorers of the West Coast glaciers were G. Mueller , G. J. Roberts, C. E. Douglas, and A. P. Harper.
Glaciers have been tourist attractions for many years. The “Hermitage” tourist hotel, near the Mueller Glacier, had been built by 1887, but was later damaged by flood waters. It was rebuilt on a new site, but destroyed by fire in 1957. A new, very modern hotel was quickly built and today is the centre of New Zealand's alpine activities. Each year thousands of tourists are taken on guided tours to the Tasman Glacier. During the winter, ski-ing is popular on the Ball Glacier, and ski-equipped aircraft take skiers to the upper parts of the Tasman, Murchison, Fox, and Franz Josef Glaciers. There have been tourist hotels at the Franz Josef and Fox Glaciers for many years. Although the West Coast glaciers have shown a marked retreat over the past 10 years, the sight of white ice cliffs in the dense rain forest continues to attract many people. The glaciers also provide access routes to the high peaks of the Southern Alps, and are traversed by many mountaineers.
by Arnold John Heine, Antarctic Division, Department of Scientific and Industrial Research, Wellington.