The Southern Ocean is the ocean that extends from 60 degrees south to Antarctica. The boundary between the Southern Ocean and the Indian, Atlantic, and Pacific Oceans is almost at the Antarctic Circle, which is 63.33 degrees south. The Southern Ocean is the fourth-largest of five principal oceanic divisions, the larger oceans between the Indian, Atlantic, and Pacific, and the smaller ocean being the Arctic.
This ocean is known for being the coldest and stormiest ocean, and the second most ice-covered ocean, after the Arctic Ocean. Icebergs are a constant hazard here, and floating ice often prevents ships from approaching the Antarctic mainland during winter. Occasionally, icebergs are the size of US states such as Connecticut.
Because there are no large bodies of land between the 50th and 60th parallels, the wind blows around the Earth continuously at these latitudes, giving them the nicknames "the Furious Fifties" and "the Shrieking Sixties." Ice-cold water also circulates the Antarctic continent in an endless eastward direction, making up the Antarctic Circumpolar Current. 30 million years ago, this current didn't exist, as it was blocked by a land connection between South America and Antarctica. At the time, large portions of the Antarctic continent were without glaciers, but the formation of the current radically cooled the entire Southern Ocean and the continent.
In some ways, the Southern Ocean is considered an opposite of the other polar ocean, the Arctic Ocean. Instead of separating continents, the Southern Ocean encircles one. Instead of being a warmer moderator of surrounding cold lands, the Southern Ocean causes the cooling of the land. Instead of being fed by rivers, the Southern Ocean is fed by glaciers which detach from Antarctica and then melt. Instead of ice forming far from the land, as is the case with the Arctic Ocean, ice in the Southern Ocean forms most alongside the land.
The Southern Ocean is famous for being the site of one of the most impressive boat voyages in history, where explorers from the Imperial Trans-Antarctic Expedition were stranded due to their primary vessel, Endurance, getting trapped in the ice. After abandoning ship, the party camped out on the ice for six months until it melted and their boarded lifeboats. They then traveled to Elephant Island, one of the northernmost islands of the Antarctic Peninsula. A small party of just six men set out in the reinforced lifeboat James Caird, traveling 800 miles (1,300 km) across the Southern Ocean to reach the island of South Georgia, where they could summon help for the rest of the party. Despite all odds, the party made it to South Georgia, the only group ever to cross the Southern Ocean in an open boat.