OK, drive down the West Coast from Hokitika, and you get in to glacier country, the 2 most famous being the Fox and the Franz Josef.
Fox Glacier is fed by four alpine glaciers, and falls 2600 metres on its 13 kilometre journey towards the coast.
Franz Josef Glacier is approximately 7000 years old, and a remnant of a much older and larger glacier which originally swept right to the sea. It extends 12 kilometres from its three feeder glaciers in the high snow fields of the Alps. The terminal face is a mere 19 kilometres from the sea and just 5 kilometres from the township.
The Fox and Franz Josef Glaciers cut through dramatic glacial valleys to flow into temperate rainforest. While many glaciers world-wide have been retreating, these glaciers still flow almost to sea level, making them unique relics of the last Ice Age.
South-Westland lies in the path of a band of wind known as the 'roaring forties'. The weather that flows on to the West Coast is forced to rise over the Southern Alps, thereby cooling and dropping most of its moisture as rain and snow. This process causes approximately 30 metres of snow to fall on the neve, or catchment area of the glacier every year. Snow that is compacted on the neve forms blue glacier ice that is funnelled down the valleys of the Franz Josef and Fox Glaciers. This flows under its own momentum, forming these 'rivers of ice' which are easily accessible from the Waiho (Franz Josef) and Cook (Fox) river beds.
Although much melt occurs from the surface of the glaciers at lower elevations (the ablation zone), this high snowfall continues to push ice down the valleys at very high rates. This is aided by basal sliding, caused by a layer of water beneath the glaciers, formed by the weight of the ice pushing against the valley floor. Both of these factors cause the Franz Josef and Fox Glaciers to have flow rates that are up to 10 times faster than most valley glaciers.