City-sized iceberg has turned into a giant swimming pool
Satellite photos show meltwater on the surface of iceberg A23a collecting in an unusual way, which may be a sign that the huge berg is about to break apart
Environment
Satellite photos show meltwater on the surface of iceberg A23a collecting in an unusual way, which may be a sign that the huge berg is about to break apart
8 January 2026
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Satellite view of iceberg A23a in the Southern Ocean, showing meltwater on its surface
NASA
Meltwater on a city‑sized iceberg in the Southern Ocean is rapidly forming a giant pool on its surface – possibly a sign that it is close to breaking apart.
Scientists are captivated by the frozen colossus, known as A23a, because meltwater is collecting and being held on its surface in an unusual way.
Satellite images reveal a raised rim of ice running around the entire cliff edge of the tabular Antarctic iceberg, giving it the appearance of an oversized children’s play pool — except this one spans about 800 square kilometres, an area larger than Chicago.
In places, the ponded water appears a deep, vivid blue, suggesting depths of several metres. Across the whole of A23a, the water volume probably runs into billions of litres – enough to fill thousands of Olympic‑sized swimming pools.
Douglas MacAyeal at the University of Chicago says the rim effect is typical of the world’s largest icebergs.
