A massive Antarctic iceberg A-81 has reached the remote South Georgia island in the South Atlantic Ocean after drifting north for more than three years. NASA satellite imagery captured on October 20, 2026, shows the iceberg slowing near the island’s shallow underwater shelf.
The iceberg which covers approximately 1,550 square kilometres broke away from Antarctica’s Brunt Ice Shelf in January 2023. It spent more than three years moving through the Weddell Sea, carried along the coast by the clockwise flowing Weddell Gyre.
By May 2026, A-81 had reached the tip of the Antarctic Peninsula before continuing north into the Scotia Sea. By late October it had travelled about 2,300 kilometres from the Brunt Ice Shelf and approached South Georgia.
According to researchers Jan Lieser of Australia’s Bureau of Meteorology and Christopher Shuman, formerly of the University of Maryland, the iceberg’s movement slowed noticeably in the days before the satellite image was captured. Its path suggested that it was moving along the edge of South Georgia’s underwater shelf, which has previously trapped or slowed large icebergs.
In 2025, iceberg A-23A ran aground on the same shelf before eventually breaking apart. Scientists are monitoring A-81’s movement to see how the underwater terrain affects its journey.
The iceberg’s formation began decades before it broke away. A major crack in the Brunt Ice Shelf, known as Chasm 1 remained relatively stable for around 35 years before beginning to grow again around 2012. By 2019, the crack was advancing rapidly, although the ice shelf remained connected for several more years before the final break in January 2023.
Iceberg formation, or calving, is a natural part of the life cycle of ice shelves. However, scientists closely monitor the Brunt Ice Shelf because it has released several large icebergs in recent years and hosts the British Antarctic Survey’s Halley Research Station, an important centre for Earth atmospheric and space science research since the 1950s.
Besides A-81 the ice shelf produced iceberg A-74 in 2021 and A-83 in 2024. A-74 has since broken apart, while A-83 remains intact and is following A-81 northward alongside other icebergs moving out of the Weddell Sea.
The latest observations were made using the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite. The imagery provides scientists with a way to track the movement of large Antarctic icebergs as ocean currents and underwater terrain influence their journeys.