The nearly 1,000-ton iceberg, known as A23a, located near Antarctica has done a twirl and spun in a circle. It’s not totally unusual for icebergs to spin, as two smaller but still massive icebergs had done so similarly on their path north, the British Antarctic Survey said Wednesday.
But A23a – it’s four times the size of New York City, according to Earth.com – began to rotate a bit sooner than other bergs. The iceberg began moving in December, breaking free from the floor of the Weddell Sea near northwestern Antarctica. It had broken off the continent’s Filchner Ice Shelf in 1986, but got stuck on the ocean floor for many years.
The British Antarctic Survey scientists described A23a’s maneuvers as part of its “spinning era … These dance moves down ‘iceberg alley’ are part of the iceberg’s long, melty journey into warmer waters,” the team wrote on Facebook, Instagram and X.
What do we know about the A23a iceberg?
The iceberg is more than twice the size of Greater London, measuring about 1,500 square miles (about 4,000 square kilometers). It had been apparently drifting for the past year and began picking up speed in late 2023, Andrew Fleming, a remote sensing expert from the British Antarctic Survey, told the BBC in November.
“I asked a couple of colleagues about this, wondering if there was any possible change in shelf water temperatures that might have provoked it, but the consensus is the time had just come,” Fleming told the BBC..
The iceberg is currently doing its spin “in a stretch of water between Elephant Island and the South Orkney Islands – small parcels of land at the tip” of the Antarctic Peninsula, the BBC reported.
Ocean and wind currents moved it into the Southern Ocean, and it is expected to continue to move northeast at about 30 miles per hour into “iceberg alley,” toward the sub-Antarctic island of South Georgia.
Assessing A23a using imagery from NASA satellites using MODIS (Moderate Resolution Imaging Spectroradiometer), the British Antarctic Survey posted that “there’s not been any major changes to the shape of the berg (though a few smaller fragments are running ahead to the North East).”
A British research team on the RRS Sir David Attenborough caught up with the iceberg on the way to Antarctica in December 2023. They collected seawater samples around the iceberg’s route to help determine what life could form around it and how the iceberg and others like it impact carbon in the ocean, Laura Taylor, a scientist working on the ship, told The Associated Press.
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