The largest iceberg ever recorded, that broke away from Antarctica’s Ross Ice Shelf 18 years ago, could be nearing the end of its voyage, according to NASA. When iceberg B-15 first broke away in March 2000, it measured about 296 kilometres long and 37 kilometres wide. B-15 has since fractured into numerous smaller bergs, and most have melted away.

Just four pieces remain that meet the minimum size requirement - at least 37 kilometres to be tracked by the US National Ice Center. When astronauts aboard the International Space Station (ISS) shot a photograph of the iceberg on May 22 this year, B-15Z measured about 18 kilometres long and nine kilometres wide.

That is still well within the trackable size, NASA said in a statement. However, the iceberg may not be tracked much longer if it splinters into smaller pieces. A large fracture is visible along the centre of the berg, and smaller pieces are splintering off from the edges.

Melting and breakup would not be surprising, given the berg’s long journey and northerly location. A previous image showed B-15Z farther south in October 2017, after it had ridden the coastal countercurrent about three-quarters of the way around Antarctica bringing it to the Southern Ocean off the tip of the Antarctic Peninsula.

Currents prevented the berg from continuing through the Drake Passage; instead, B-15Z cruised north into the southern Atlantic Ocean. When the May 2018 photograph was acquired, the berg was about 277 kilometres northwest of the South Georgia islands. Icebergs that make it this far have been known to rapidly melt and end their life cycles here.