COLUMBIA ICEFIELD

largest ice field in the Rocky Mountains, astride the British ColumbiaAlberta border, Canada. Lying partially within Jasper National Park, it is one of the most accessible expanses of glacial ice in North America. It forms a high-elevation ice cap on a flat-lying plateau that has been severely truncated by erosion to form a huge massif. The glacial area extends between the summits of Mount Columbia (12,294 feet [3,747 metres]) on the west and Mount Athabasca (11,452 feet [3,491 metres]) on the east. The eastern side of the ice field is reached by paved highway from Banff, 100 miles (160 km) south, and from Calgary, another 80 miles (130 km) away to the southeast. Although the ice field embraces some 100 square miles (300 square km) of glacial ice extending from its summit plateau to the termini of a dozen outlet glaciers, it is relatively small compared with such vast ice fields of the Alaska-Canada border region as the Juneau Icefield, near Alaska's capital city, Juneau, and the ice sheets of the northeastern Arctic on Ellesmere Island and Greenland.