- A23a iceberg drifted from Antarctica for decades before ending its journey in 2026
- Soviet Druzhnaya 1 station was carried away on iceberg A23 in 1986 near Filchner Ice Shelf
- A23 split in 1991, forming A23a which remained trapped in Weddell Sea for many years
A giant iceberg that drifted across Antarctica's waters for decades has finally reached the end of its remarkable journey.
The story of A23a began in the mid-1970s, when the Soviet Union established the seasonal Druzhnaya 1 research station near the Filchner Ice Shelf in Antarctica, reported National Geographic.
For years, Soviet scientists came back every Antarctic summer to work there. But when they got ready to return in October 1986, they discovered a major problem, they could no longer find the place they were supposed to go. The Soviet news agency TASS reported that the station had evidently drifted away on an undetected iceberg and suggested it might have been carried on a small piece of ice that had overturned, making it impossible to recover. However, later investigations showed the station had drifted away on a much larger iceberg.
Scientists found that a massive section of the Filchner Ice Shelf had broken away in a calving event, splitting into three icebergs named A22, A23, and A24. Druzhnaya 1 had been carried away on A23.
In January 1987, a Soviet team landed on the iceberg and spent two weeks recovering valuable equipment buried beneath snow. It is believed to have been the last time people set foot on A23.
In 1991, A23 split into several pieces, with the largest fragment named A23a. Measuring about 2,000 square miles, roughly the size of Bali, it remained trapped in the Weddell Sea for many years, held in place by sea ice and grounded on the ocean floor. Meteorologist and marine glaciologist Jan Lieser noticed the iceberg during the late 1990s while tracking another iceberg but did not expect it to become the focus of worldwide attention.
Only in 2020 did A23a begin to move. The United States National Ice Center announced that A-23A was on the move after it rotated several nautical miles. More than a year later, it began drifting with the Weddell Gyre current, travelling nearly 1,000 nautical miles over the next two years. By then, it covered about 1,500 square miles and had regained the title of the world's largest iceberg, reported National Geographic.
As A23a entered the Southern Ocean in late 2023, it drew global attention. Scientists said its movement was likely a natural process rather than the result of climate change. During its journey, researchers and expedition teams studied the iceberg, collecting water samples and observing how its melting influenced the surrounding marine environment.
In March 2024, A23a became trapped in an oceanic gyre and spun repeatedly for several months, a rare event scientists linked to a phenomenon known as a Taylor column caused by an underwater mountain. After breaking free in late 2024, the iceberg continued drifting through warmer waters while gradually shedding ice.
In early 2025, remnants of the Soviet Druzhnaya 1 station, including rusted barrels and storage tanks, emerged from the melting ice after being carried for more than 38 years and around 2,000 miles. The iceberg later approached South Georgia before grounding on an underwater ridge and eventually moving away again.
By June 2025, A23a had shrunk below 1,200 square miles and lost its title as the world's largest iceberg. Scientists expected it to continue thinning, fracturing, and breaking apart as it entered warmer waters, reported National Geographic.
The end came in March 2026, when the United States National Ice Center reported that A23a had become too small to continue tracking. Although some small fragments may still remain, researchers believe the giant iceberg's long journey has effectively come to an end. Its decades-long voyage from Antarctica to the Southern Ocean has offered scientists a rare opportunity to study the life cycle of one of the largest icebergs ever recorded.
