Ross Ice Shelf
The southern half of the Ross Sea is overlain by the world’s largest floating ice shelf, the Ross Ice Shelf, which extends up to 280 miles (450 km) from the shore of Antarctica. The Norwegian explorer Roald Amundsen started his successful expedition to the South Pole in 1911 by crossing this ice shelf. It ranges in thickness from about 820 ft (250 m) at the ice front to 2,600 ft (800 m) inland. Ice floats with most of its volume underwater, making the height of the ice front above sea level about 65–100 ft (20–30 m). The shelf flows seaward at about 3,000 ft (900 m) per year, propelled by the accumulating weight of compacted snow that falls on the high plateau of the Antarctic Ice Sheet. Accumulation on the ice cap is thought to be balanced by iceberg calving at the front of Antarctica’s ice shelves and melting on their underside.