Journey of Antarctica’s A-68A: The voyage of one of the planet’s largest icebergs
The Delaware-sized iceberg that broke from Antarctica in 2017 finally melted away in 2021.
These images highlight its long journey across the Southern Ocean and into southern Atlantic waters.
Growth of a Rift
The Larsen A and B ice shelves disintegrated two decades ago.
January 2016: The Larsen C ice shelf appeared poised to calve one of the largest icebergs ever recorded.
August 2016: Sunlight returned to the Antarctic Peninsula, exposing a rift across Larsen C that had grown longer and deeper over the austral winter.
November 2016: NASA scientist John Sonntag snapped this photo of the rift during a flight of NASA’s Operation IceBridge mission.
November 2016: It measured about 100 meters wide and cut completely through to the bottom of the ice shelf.
June 2017: Though shrouded in winter darkness, the rift was still visible to some satellites.
Scientists with the UK-based Project MIDAS used satellite radar to monitor the rift through the winter.
An Iceberg is Formed
July 2017: The rift finally broke through, forming the ‘Delaware-sized’ iceberg.
Reflected moonlight helped satellites capture this view of the berg just after the big break.
July 2017: Two weeks after the initial break, satellite thermal images showed two large icebergs—including A-68A—and several smaller pieces.
September 2017: Subtle features began to emerge as daylight illuminated the new iceberg.
November 2017: Operation IceBridge flights resumed, giving scientists a close-up look at A-68A.
July 2018: One year after the big break, A-68A had only moved a short distance—roughly 45 kilometers from the shelf.
Drifting North
April 2020: A-68A eventually picked up the pace, floating northward into warmer waters.
April 2020: Then it hit the brakes and rotate in place—possibly caught up in a whirling mass of ocean water, or “gyre.”
November 2020: Escaping the gyre, the iceberg approached South Georgia, a remote island in the southern Atlantic Ocean.
December 2020: Scientists around the world waited to see what the berg would do next.
December 2020: As it approached shallow water, the berg could have gotten stuck, or “grounded,” with worrisome consequences for penguins and other near-shore marine life.
December 2020: But it started to drift away and around the island, steered by large and powerful currents.
December 2020: While making the maneuver, a block of ice measuring almost 180 square kilometers broke off.
January 2021: Dramatic changes continued, as seawater started cutting through the iceberg.
February 2021: More icebergs splintered away from A-68A. On February 12, eleven bergs were large enough to be named and tracked.
April 2021: Only a sliver of the original A-68A was all that remained, surrounded by icebergs too small to be named.
April 2021: Fracturing and changing shape daily in the South Atlantic Ocean, the iceberg left no question that the end was near.
A-68A ultimately broke apart and melted away by the middle of the month.
April 2021: The iceberg’s demise ends an almost four-year voyage full of twists and turns.
But all is not lost. Satellite images captured during the event will help scientists study the natural life cycles of Antarctic ice shelves and icebergs yet to come.