A23a has been almost stationary for several months, spinning slightly counterclockwise – about 15 degrees per day. As he describes BBCa huge iceberg has fallen into the trap of a vortex that may trap it for a long time and prevent it from breaking up. “A23a is an iceberg that just won't die,” Professor Mark Brandon, a polar seas researcher from the Open University, told the British portal.
A23a is stuck
The mountain is stuck north of the South Orkney Islands, Antarctic islands located to the north-east of the Antarctic Peninsula (incidentally, to the north-west of the peninsula, much closer to it than Orkneythere is King George Island with the Polish Antarctic Station).
The path to the vortex trap began for this mountain in 2020. Although A23a broke away from Antarctica in 1986, for the next three decades it was de facto an “island” – it was attached to the bottom of the Weddell Sea (this is an Antarctic coastal sea, part of the Southern Ocean). At the end of 2023, it turned out that began to drift towards “iceberg alley.” In April of this year, she was swept into the Antarctic Circumpolar Current, which should have catapulted her toward the South Atlantic (and a slow death). Instead, she got stuck in a kind of vortex, a phenomenon called the Taylor Column.
A23a is the largest iceberg in the world. It has a surface area of about 4,000 km2. As the BBC graphically shows, it would barely fit in the English Channel. Seen from the water, it looks like a giant, almost perfect plateau – but of course most of it is below the sea surface. The thickness of this formation can be as much as 300 meters.
Where did A23a come from?
Before it became a separate entity, it was part of the Filchner Ice Shelf in West Antarctica. Ice shelves are huge masses of ice floating on water, but still connected to land. They act as a kind of “plug” that blocks the glaciers on land from flowing into the sea. When the shelf disintegrates, this protection ceases to function. Such phenomena occur primarily in the western part of Antarctica, which is perceived as less stable than the larger, eastern part. However, for several years there have been signs that East Antarctica, considered more “safe”, is beginning to undergo change climate.
Scientists quoted by the BBC point out that what is happening to A23a now is related to the shape of the seabed. They were able to determine this because the area around the mountain's rotation is relatively well-studied. As the BBC emphasizes, only a quarter of the seabed is mapped according to the best modern standards.
“Antarctica is a mighty continent, larger than Europeand we have only been studying it seriously for about 40 years. And it is almost like doing research on another planet” – the interview with Prof. Sławomir Tułaczyk, a glaciologist from the University of California in Santa Cruz, can be read at this link: Disturbing Signals from East Antarctica. And He Was Supposed to Be Untouchable. Prof. Tułaczyk: It's Not Good.