Researchers have discovered the missing piece of the puzzle behind a rare opening in the sea ice around Antarctica, which was nearly twice the size of Wales and occurred during the winters of 2016 and 2017.

This phenomenon, which was initially observed in 1974, manifests near Maud Rise—a submerged elevation—and is not a consistent occurrence, prompting questions about its formation. The hole’s sporadic reappearances in 2016 and 2017 incited a comprehensive investigation employing satellite imagery,

In the winter ice crusting over the Antarctic Weddell Sea, near a submerged peak named Maud Rise, a huge hole sometimes opens and gapes, exposing the dark, cold waters below. First spotted in 1974, it doesn't appear every year, leading scientists to wonder about the specific conditions needed to produce it.

During the winters of 2016 and 2017, a hole the size of Switzerland opened in the middle of Antarctica's sea ice. And scientists just figured out how it came to be.