The iceberg cometh: It's the size of Oahu, and it's moving into the open ocean

The world's largest iceberg, A23a, is moving into the open waters near Antarctica after being essentially stuck in place for decades. It's seen here in satellite imagery from Nov. 15. (European Union/Copernicus Sentinel-3/via Reuters)

Ships plying the frigid waters near the Antarctic Peninsula, south of South America, will need to keep an eye on their radar for a floating island of ice: "The largest iceberg in the world, A-23a, is on the move into open ocean!" as the British Antarctic Survey recently announced.

"It's a trillion tons of ice. So it's hard to comprehend just how big a patch of ice this is," Ted Scambos, a senior research scientist at the University of Colorado Boulder, told NPR.