December 17, 2020

Huge iceberg A68a grounded near South Georgia

Recent data recorded by TerraSAR-X show that the northern end of iceberg A68a obviously ran aground near South Georgia, causing a large piece of the iceberg to break off. With its immense size of 145 km in length and 45 km in width it is almost as large as the island itself.

According to the latest assessments it has rotated back toward the south and abandoned its direct course of collision with the island. However, it is still very near the critical ocean depth of 200 metres, so it could still become entirely grounded on the ocean floor and remain at South Georgia for some time. This scenario would represent a serious threat for the hundreds of thousands of penguins and seals living on South Georgia. Because of its length, A68a could block off access to feeding grounds, which would have grave effects on the fauna of this South Atlantic island.

Ob der Eisberg nun wieder in tiefere Gewässer gelangt und die Gefahr tatsächlich gebannt ist, ist schwer vorherzusagen, da die Driftrichtungen immer von den aktuellen Meeresströmungen und der Meerestopographie abhängen.

Der riesige Eisberg ist bereits seit drei Jahren unterwegs, nachdem er im Juli 2017 am Larsen-C-Schelfeis an der Ostseite der Antarktischen Halbinsel gekalbt war. Seitdem driftet der Koloss im westlichen Weddellmeer langsam nach Norden und hat mittlerweile mehr als 1700 Kilometer zurückgelegt.

It is difficult to predict whether the iceberg will retreat to deeper water so that this danger is averted, since the direction of drifts always depends on the momentary ocean currents and the ocean topography.

The enormous iceberg has been underway already for three years after calving from the Larsen C ice shelf on the eastern side of the Antarctic Peninsula in July 2017. Since then the colossus has been slowly drifting northward in the western Weddell Sea and has in the meantime covered a distance exceeding 1,700 kilometres.

Unforgotten: South Georgia and Shackleton

South Georgia is primarily known because of the British polar researcher and adventurer Sir Earnest H. Shackleton. As expedition leader he left South George on the “Endurance” with 28 men in December 1914, heading toward the Weddell Sea. The first goal was an anchor point of the Filchner-Ronne ice shelf, where he wanted to set out for the south pole with a team of six companions.

Despite the Antarctic summer the ship became quickly encased in sea ice, so Shackleton had no choice but to drift with the pack ice and spend the winter on the ship. However, in October the pressure of the drifting ice had become so great that the ship was slowly crushed and finally sank on November 21st. The crew erected various winter quarters on the sea ice, and only on April 9, 1916 were they released from the drifting pack ice. In three lifeboats from the Endurance the crew was able to reach Elephant Island after almost 500 days at sea and in sea ice. But since there was scant chance of rescue by whalers from that location, Shackleton set out for South Georgia with five men in the small "James Caird” lifeboat on April 24, 1916 to arrange a rescue mission. After unspeakable hardship they reached King Haakon Bay in north-western South Georgia on May 8 after a1500-kilometre journey in one of Earth’s stormiest seas. In a final effort Shackleton and two comrades actually managed to traverse the island in a 36-hour forced march over passes and glaciers that had never before been crossed. On May 20, 1916 they reached Stromness whaling station on the north-eastern coast of the island. The expedition had set out from there a year and a half earlier.

But it took another three months and three futile rescue attempts before Shackleton could reach his 22 remaining men on Elephant Island on 30 August 1916 with the Chilean schooner Yelcho from Punta Arenas and finally rescue all expedition participants.

Shackleton died on 5 January 1922 at Grytviken harbour on South Georgia, where he was about to begin another expedition to the Antarctic. At the request of his wife, Shackleton was buried on South Georgia. Thus his name and the Endurance Expedition have become a permanent part of the history of South Georgia.

Endurance among ice pinnacles, Shackleton expedition, February 1915
The sinking Endurance
The lifeboat “James Caird” sets off from Elephant Island on a rescue mission with a 6-man crew.

Further reading:

Frank A. Worsley (1931): Der Untergang der Endurance. First German edition, 2000, Ullstein-Verlag, Munich. (The original text by the captain of HMS Endurance appeared in 1931 under the title Endurance – An Epic of Polar Adventure)

Caroline Alexander (2019): The Endurance - Shackleton‘s Legendary Antarctic Expedition. Alfred Knopf-Verlag, New York, with many photographs taken by Frank Hurley, expedition photographer, published for the first time