The southern Alps form a high mountain barrier along the western side of the south island of New Zealand. The highest point is Mount Cook at 3,764 m {12,349 ft}; it is only 32 km {20 miles} from the summit westward across the coastal strip to the pacific Ocean. To the east the land descends more gradually for 130 km {80 miles} across  the canterbury plains to the coast. The westerly winds that b;ow in from the Tasman sea are laden with moisture, and as the damp air rises against the mountains it drops heavy snowfall along the range that feed the glaciers. The three most famous are the Tasman, Fox and Franz Josef glaciers.

The glaciers on the western side of the mountains are short and steep, tumbling downward like frozen cataracts that reach into the dense, subtropical evergreen rainforests in an extraordinary juxtaposition. On the eastern side of the range the glaciers are quite different in character, with the higher reaches typically steep and rugged, patterned by networks of crevasses that make travel difficult. Lower down, these glaciers flow to low altitudes, and the Tasman Glaciers reaches almost as far as the plain.