Images of the largest iceberg in the world have been snapped by NASA as it drifts toward its doom in warmer waters.
The iceberg, named A-23A (sometimes called A23a), just escaped from an ocean current vortex that had trapped it just to the north of the South Orkney Islands for months, rotating anticlockwise more or less on the spot at a rate of about 15 degrees every day.
Now, the iceberg has broken free of this watery cage and is floating northeast in the direction of South Georgia Island, where it is expected to break up and melt into oblivion.
NASA images reveal the journey of this gargantuan slab of ice as it made a break for the open waters of the Southern Ocean, finally escaping the grips of Antarctica.
These pictures were snapped by the MODIS (Moderate Resolution Imaging Spectroradiometer) and VIIRS (Visible Infrared Imaging Radiometer Suite) instruments on several NASA and National Oceanic and Atmospheric Administration satellites.
As of Friday, A-23A is about 1,062 square miles in area, according to the U.S. National Ice Center, making it about twice the size of Los Angeles. The iceberg was previously bigger, about the size of Rhode Island, having reached an area of 1,700 square miles in November 2023.
In 1986, A-23A initially broke off from the Filchner-Ronne Ice Shelf near the Antarctic Peninsula but almost immediately became grounded on the seafloor in the southern Weddell Sea. The iceberg remained there for over 30 years until it finally floated free in 2020, likely because of melting, and floated northward along the Antarctic Peninsula. Then, in the summer of 2024, A-23A became trapped in a Taylor column -- a rotating current -- above a bump on the ocean floor called the Pirie Bank.
"It's exciting to see A23a on the move again after periods of being stuck. We are interested to see if it will take the same route the other large icebergs that have calved off Antarctica have taken," said Andrew Meijers, an oceanographer at the British Antarctic Survey and co-lead of the OCEAN:ICE project, in a statement.
Over 90 percent of Antarctic icebergs end up floating in a clockwise-flowing current called the Weddell Gyre, skirting along the eastern coast of the Antarctic Peninsula just as A-23A initially did. This route is named Iceberg Alley and is the final route of most icebergs as they are propelled northward into warmer waters to their inevitable demise.
However, some icebergs take some detours along the way, including iceberg A-68A, which looped around in the Drake Passage for a while in 2017, and A-23A itself. During its time in the Taylor column, A-23A was seen making 15 total revolutions as it spun.
"I am not aware of an iceberg that has been trapped in such a persistent manner in such a small area," said Jan Lieser, an ice specialist at the Antarctic Meteorological Service who has been tracking A-23A, in a NASA Earth Observatory blog post.
The iceberg has traveled about 150 miles since escaping the Taylor column, heading northeast. Exactly what caused the emancipation of A-23A from the current remains unknown.
"My hypothesis is that a random perturbation in the system might have triggered a slight variation of the 'usual' spin, such that the iceberg found an exit path," Lieser said.
In the coming months, A-23A will slowly shrink, breaking apart and melting, and the "largest iceberg" title will go to another.