Unusually clear skies allowed the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite an unobstructed view of a snow-and-ice covered South Georgia on September 29, 2012. As MODIS passed over the South Atlantic Ocean, two big icebergs and a number of smaller ice chunks floated around the island.
Off the island’s northwestern tip was Iceberg C-19C, measuring 35 by 28 kilometers (19 by 15 nautical miles), according to the U.S. National Ice Center. The iceberg is a remnant of the larger Iceberg C-19, which calved off Antarctica’s Ross Ice Shelf in May 2002. To the southeast is Iceberg B-15F—measuring 35 by 7 kilometers (19 by 4 nautical miles)—a remnant of Iceberg B-15, which calved off the Ross Ice Shelf in March 2000. South Georgia itself is just 170 kilometers (105 miles) from northwest to southeast.
The presence of icebergs in this region is not unusual. In January 2004, much larger icebergs congregated off South Georgia’s shores. Ted Scambos of the National Snow and Ice Data Center explained that Antarctic icebergs tend to get caught up in deep ocean currents that return the icebergs to this region again and again.
The island is not easy to traverse, as Antarctic explorer Ernest Shackleton discovered on his first attempt to reach the South Pole. He left the island on the Endurance in December 1914. Seventeen months later, he returned in a lifeboat, having left most of his crew waiting for rescue on Elephant Island. Severely damaged, the lifeboat limped into King Haakon Bay. Shackleton and two other crew members trekked across the island to the Stromness Whaling Station for help.
The journey entailed climbing over high peaks and glaciers. This astronaut photograph gives a glimpse of the rugged terrain, where 11 summits exceed 2,000 meters (6,000 feet) in altitude. Geologists have proposed that this mountainous island is a continuation of the Andes in South America.
When MODIS captured this image, wisps of blue-green colored the water off the island’s southwestern coast. Norman Kuring of the Ocean Color Team at NASA’s Goddard Space Flight Center explained that the color likely comes from glacial flour. South Georgia is home to numerous glaciers, which slowly grind the underlying rocks to fine, powdery sediment that washes out to sea.
- Government of South Georgia and the South Sandwich Islands. The Island. Accessed October 5, 2012.
- National Ice Center. (2011, November 27). Current Antarctic Iceberg Positions. Accessed October 2, 2012.
- PBS NOVA. (2002, February) Shackleton’s Antarctic Odyssey: 1914–1916 Timeline. Accessed October 5, 2012.
- Storey, B.C., Macdonald, D.I.M. (1984) Processes of formation and filling of a Mesozoic back-arc basin on the island of South Georgia. Geological Society, London, Special Publications. 16, 207–218.
- WGBH and PBS. (2000) Shackleton’s Antarctic Adventure: The Climbers. Accessed October 5, 2012.
NASA image courtesy Jeff Schmaltz, LANCE MODIS Rapid Response Team at NASA GSFC. Caption by Michon Scott.
- Terra - MODIS