An Iceberg the Size of Rhode Island Was Stuck Spinning Near Antarctica — Then, a Miracle Happened

Even the world’s largest iceberg is not big enough to escape the clutches of Earth’s vast oceans. A23a, an iceberg the size of Rhode Island, has been stuck spinning in the frigid waters close to Antarctica since late 2024. The satellite images show that the iceberg is rotating counterclockwise about 15 degrees a day. However, NASA scientists were clueless about how long this phenomenon may occur, as reported by Fox Weather.  Icebergs that break off from an ice shelf or glaciers tend to drift away with the ocean’s currents, shift with the tides, or be blown by the wind. Sometimes they get stuck on the seafloor or rotate under the influence of a whirling mass of water beneath, according to NASA’s Earth Observatory.

A23a checked all the boxes soon after it calved off from the Filchner-Ronne Ice Shelf on the northwestern side of Antarctica in 1986. The iceberg was last captured north of the South Orkney Islands of Antarctica through satellite imagery. The naming of the iceberg done by the U.S. National Ice Center (USNIC), is coded with information about its origins– ‘A’ denotes the Weddell Sea quadrant, ‘23’ suggests it is the 23rd iceberg in the quadrant tracked by the organization, and ‘a’ indicates that it was the main/parent iceberg. 

Experts have identified that the spinning motion of A23a is caused due to a column of whirling water called a “Taylor Column”, said to be caused by currents interacting with a bump on the sea floor. The movement caught the iceberg in April 2024 while riding the ocean currents from the Weddell Sea to the Southern Ocean. There was no prior estimate on how long it may remain trapped inside the column. In general, objects can remain trapped in the Taylor Column from a few days to several years. Jan Lieser, an ice specialist working with the Antarctic Meteorological Service, has tracked A23s making 15 revolutions between March and November last year. He said, “I am not aware of an iceberg that has been trapped in such a persistent manner in such a small area.” 

The pathway that the world’s largest iceberg had embarked on, known as “Iceberg Alley”, typically pushes it to warmer waters where it would eventually melt. However, before A23a reached the warm waters it first got stuck on the Weddell Sea floor for several years until releasing itself free in 2020, about 34 years later. As the berg had free-floated on the tides and ocean currents, it was pulled into Taylor’s Column where its circular motions caught scientists’ attention. Christopher Shuman of the University of Maryland, Baltimore, explained that the berg drifted 240 kilometers in one month after exiting the whirling waters. 

The experts are unsure of what may have caused the departure but hypothesized that a “random perturbation” probably allowed the berg to find an exit from the spinning trap. “This serves to remind us both of the mysteries of our oceans and the value of remote sensing data,” Shuman noted. To put things into perspective, the A23a is three times the size of New York City and is heading towards the Southern Ocean if following the conventional Iceberg Alley path. There is discussion around the drastic environmental impacts if and when the world’s largest iceberg melts, causing sea levels to surge and unpredictable climatic events.