McMurdo Sound

The ice-clogged waters of Antarctica's McMurdo Sound extend about 55 km (35 mi) long and wide. The sound connects the Ross Sea to the north with the Ross Ice Shelf Cavity to the south via Haskell Strait. The strait is largely covered by the McMurdo Ice Shelf. The Royal Society Range rises from sea level to 13,205 feet (4,205 m) on the western shoreline. Ross Island, an historic jumping-off point for polar explorers, designates the eastern boundary. The active volcano Mt Erebus at 12,448 feet (3,794 m) dominates Ross Island. Antarctica's largest scientific base, the United States' McMurdo Station, as well as the New Zealand Scott Base are located on the southern shore of the island. Less than 10 percent of McMurdo Sound's shoreline is free of ice.

Captain James Clark Ross discovered this sound, which is about 800 miles (1,300 km) from the South Pole, in February 1841, and he named it after Lt. Archibald McMurdo of the HMS Terror. The sound today serves as a resupply route for cargo ships and for airplanes that land on the floating ice airstrips near the McMurdo Station. However, McMurdo Station’s continuous occupation by human beings since 1957-58 has turned Winter Quarters Bay into a harbor with water pollution.

The pack ice that girdles the shoreline at Winter Quarters Bay and elsewhere in the sound presents a formidable obstacle to surface ships. Vessels require ice-strengthened hulls and often have to rely upon escort by icebreakers. Such extreme sea conditions have limited access by tourists, who otherwise are appearing in increasing numbers in the open waters of the Antarctic Peninsula. The few tourists who reach the McMurdo Sound find spectacular scenery with wildlife to be seen, including killer whales, seals, Adelie penguins, and Emperor penguins.

Cold circumpolar currents of the Southern Ocean reduce the flow of warm South Pacific or South Atlantic waters reaching McMurdo Sound and other Antarctic coastal waters. Bitter katabatic winds spilling down from the Antarctic polar plateau into McMurdo Sound demonstrate Antarctica's status as the coldest and windiest continent in the world. The McMurdo Sound freezes over with sea ice about 10 feet (3.0 m) thick during the winter. The Antarctic summer causes the pack ice to break up. Wind and currents may push the ice northward into the Ross Sea, stirring up cold bottom currents that spill into the ocean basins of the world. Temperatures during the dark winter months at McMurdo Station have dropped as low as −59 °F (−51 °C). However, December and January are the warmest months, with average highs at 30 °F (−1 °C) and 31 °F (−1 °C) respectively (USA Today).