— the largest on Earth — is on the move after being trapped in a giant vortex for months
The "megaberg" A23a is on the move again after spinning in one spot for months on end. This is the ice slab's second great escape in as many years after being stuck in place for the first 37 years of its existence.

The world's largest iceberg is on the move again after escaping from a giant vortex that caused it to spin in place for months. This is the big berg's second great escape in as many years, after breaking free from the seafloor where it was stuck for 37 years in 2023.Scientists are now closely monitoring the icy slab's slow march toward oblivion in hopes of learning more about the temporary hidden ecosystem it may support.A23a, which is often dubbed a "megaberg," has a surface area roughly three times larger than New York City and weighs just under 1 trillion tons. It first broke off from Antarctica's Filchner Ice Shelf in 1986 but became trapped on the seafloor just a few miles offshore, which has significantly slowed its melt rate. Over the last few decades, it has held the title of "world's largest iceberg" on multiple occasions, most recently since May 2023, when the previous largest berg — A-76A — broke apart.Late last year, A23a finally broke free from its seafloor tether and began moving away from Antarctica. But it didn't get far. Just a few months later, the enormous ice island got trapped to the east of the South Orkney Islands in a Taylor column — a giant mass of rotating water caused by ocean currents circling an underwater mountain, or seamount. At its maximum spin speed, the berg was rotating about 15 degrees counterclockwise every day, researchers wrote on YouTube. Read More »