Antarctic Icebergs

Antarctic Icebergs

Some of the biggest icebergs in the world break off from Antarctica’s ice shelves. One iceberg, called B15A, was over 115 kilometers long and the same size as Jamaica. Because the density of the freshwater ice is slightly less than that of the surrounding seawater, only 10 percent of an iceberg is typically visible above the water—hence the saying, “tip of the iceberg”. Icebergs gradually melt as they drift farther away or become grounded in shallow water. Here they can be sculpted by the waves and frozen into the sea ice to form huge towers of ice.


Video: British Antarctic Survey
Text: British Antarctic Survey and WGBH Educational Foundation