The world’s largest iceberg has been spinning in the same spot for the last few months – and it may continue to do so for quite some time.
The British Antarctic Survey confirmed in a post on X that the iceberg, known as A23a, has yet to make its “melty journey north.”
“This Cornwall-sized piece of ice is now just spinning in an ocean vortex near the South Orkney Islands, maintaining a chill 15-degree rotation per day,” BAS wrote.
The English county of Cornwall has an area of approximately 3,550 square kilometres.
A23a broke a Guinness World Record in February for being the largest iceberg ever recorded, coming out at around 3,900 square kilometres (about double the size of Greater London, U.K., or four times New York City).
Looking at Canadian equivalents, one area that comes close is Greater Sudbury, Ont., which is approximately 3,200 square kilometres, according to Statistics Canada. Quebec’s Val-d’Or is between 3,500 and 3,900 square kilometres, depending on the source of the estimate.
To put that into perspective further, the City of Toronto is only about 640 square kilometres, according to the municipal government, but factoring in the Greater Toronto Area brings the size out to between 5,900 and 7,000 square kilometres, depending on the boundaries being used.
The iceberg is about two-thirds the size of Prince Edward Island.
The mega-iceberg originated from the Filchner-Ronne Ice Shelf, located on the northwestern side of Antarctica. According to NASA, iceberg A23a split off from the shelf in 1986 and remained in the Weddell Sea, just off the western coast of Antarctica, about 200 kilometres away.
It unstuck from the seafloor and started moving again in 2020, which NASA says was likely due to melting below the waterline.
The iceberg rode the currents around the Weddell Sea for most of the summer of 2023, but by that November, it spun around the currents near the tip of the Antarctic Peninsula.
Scientists at the BAS used satellite imaging to track the tremendous iceberg on its journey into the Antarctic Ocean, with a group of its members sailing past the iceberg in December.
The iceberg remained there until February when performed a “full pirouette” before drifting toward a northerly current, NASA said.
Kent Moore, professor of theoretical geophysics of climate change at the University of Toronto Mississauga, told CTVNews.ca that it was believed in April that iceberg A23a would continue to head north and melt, but instead, it got stuck in a phenomenon known as a Taylor column.
Moore said the best way to understand a Taylor column is to picture a hockey puck in an aquarium full of water.
“If you drag that hockey puck along the bottom of the tank, then what’s going to happen is the water is going to be forced to go around the puck right at the bottom, but above the hockey puck, the water is going to be undisturbed,” Moore said in an interview Tuesday. “But the earth is rotating, and so if you take that same aquarium and you put it on a big turntable and spin it, and you do the same thing, it turns out that even above the hockey puck, the water is forced to go around it.”
Seamounts, or underwater mountains, act like that hockey puck, Moore said, and the colossal iceberg is spinning around as a result.
“It’s going to sit there now probably for quite a while … it probably won’t escape, it’ll just plain melt within that Taylor column,” Moore said.
The U.S. Ice Center reported the mega-iceberg’s location roughly halfway between the tip of the Antarctic Peninsula and South Georgia Island, near the South Orkney Islands, in the Antarctic Circumpolar Current (ACC) as of Aug. 2.
The ACC is the world’s largest ocean current, and according to the United Nations, it is the only global current circulating water to the Atlantic, Pacific and Indian oceans. It also plays a part in the warming seen in the Antarctic Ocean, also known as the Southern Ocean.
It’s quite rare for an iceberg to get stuck in one of these phenomena, Moore said, since there are only a few known columns.
“I don’t think it’s happened before,” Moore added.