16 January 2026
A year ago the world’s largest iceberg was on a collision course with South Georgia Island, home to millions of penguins including king and macaroni species. A23a was larger than Rhode Island back then and if it lodged against the South Georgia shore it would block ocean access for all the penguins and they would starve.
In February 2025, A23a (the square white thing) seemed to dwarf South Georgia Island.
But the dire predictions never materialized.
As NASA satellites continued to track A23a, it wandered and spun its way around South Georgia Island, then struck bottom west of the island in March 2025 where it has been melting in place ever since.
NASA sometimes describes this area of the South Atlantic as the “iceberg graveyard.”
Water at this latitude—about 54 degrees South—is generally warmer than the Southern Ocean [that surrounds Antarctica] and is deadly for icebergs. When Southern Hemisphere winter ends in late September / early October the return of abundant sunlight further warms the water. The lack of sea ice in the vicinity of an iceberg implies that the water is above the freezing point.
— (paraphrased) NASA: A Place Where Icebergs go to Die
This month it was obvious, even from satellite, that A23a is disintegrating. Meltwater is ponding on the surface — visible as blue water — and trickling through the cracks in the ice, further weakening it.
This closeup shows striations and melt ponds.
Poseidon Expeditions paid a visit to A23a before the surface turned blue.
By now A23a is 40 years old but its days are numbered. Breaking up is easy to do in the iceberg graveyard.
