World's biggest iceberg A-23A turns blue as it nears collapse

NASA images and an ISS photograph show iceberg A-23A covered in surface meltwater and large blue melt ponds, and scientists report these features indicate the iceberg could collapse within days or weeks.

A-23A, long tracked by researchers, now shows widespread surface meltwater and blue melt ponds in recent satellite and space-station imagery. The iceberg broke away from Antarctica's Filchner Ice Shelf in 1986 and has been drifting in the Southern Ocean since. Scientists report the current surface patterns and signs of structural weakening point to imminent disintegration. Known details: - NASA's Terra satellite captured images on December 26 showing extensive melt ponds and blue surface areas, and an astronaut aboard the International Space Station photographed an even larger melt pond on December 27. - A-23A separated from the Filchner Ice Shelf in 1986 and once covered about 1,540 square miles; the US National Ice Center estimated its area had fallen to roughly 456 square miles in January. - Researchers including Dr Chris Shuman and Dr Tedd Scambos say the meltwater pooling and signs of edge weakening suggest the iceberg could collapse within days or weeks. Summary: The observed meltwater features mark a rapid late stage for a long‑lived iceberg. Scientists expect total breakup is likely soon, and the precise timing is undetermined at this time.