The Long Final Voyage of A23a, the World's Largest Iceberg

After drifting for nearly four decades and traveling over 2,000 miles, the massive iceberg A23a has officially vanished from tracking records. Once the size of Bali, the frozen behemoth that famously carried away a Soviet research station in 1986 has finally succumbed to the warming waters of the Southern Ocean.

Editorial·July 14, 2026·reads: 488

The Long Final Voyage of A23a, the World's Largest Iceberg

The iceberg’s history traces back to the mid-1970s, when the Soviet Union established the Druzhnaya 1 station near the Filchner Ice Shelf. In 1986, the station vanished, only for investigators to realize it had been swept away during a calving event that birthed A23. By 1991, the formation split, leaving A23a as a 2,000-square-mile titan grounded on the seafloor of the Weddell Sea. It remained trapped there for decades until it began to rotate in 2020, eventually entering a current that propelled it into the open ocean.

During its transit, the iceberg became a floating laboratory. In early 2025, the melting ice finally surrendered the remnants of the Druzhnaya 1 station—rusted barrels and storage tanks that had been encased in the glacier for 38 years. By June 2025, the iceberg had shrunk to less than 1,200 square miles, shedding its title as the world's largest. The United States National Ice Center confirmed in March 2026 that the fragment had reached a size too small to monitor, marking the conclusion of a rare, decades-long journey that provided scientists with unique insights into the life cycle of Antarctic ice.