The icebergs vary in size, but are typically irregular with pinnacles. About seven-eighths of an iceberg is submerged. Thus iceberg drift is affected more by ocean currents than by wind. When they drift into shipping lanes, they become a serious hazard. More than 1,500 passengers and crew perished.
Icebergs are rare in the Arctic Ocean although extensive sea ice exists year-round.
In Antarctica, they are common and gigantic. Due to their size and the cold temperatures of Antarctica, they can survive up to ten years. A mammoth iceberg the size of Rhode Island was sighted off the coast of Antarctica during the summer of 1996. It had apparently split from the coast of East Antarctica a few months earlier. The iceberg, with sheer walls rising 100 to 160 feet above the water line, extends into the water to a depth of 1,000 feet.