The largest iceberg in the world is a behemoth known as A23a. It spans some 40 miles (65 km) across. It’s 1,312 feet (400 m) thick. It calved from Antarctica’s Filchner Ice Shelf decades ago, in August 1986. But almost immediately it grounded on the seafloor, and so was locked in place for decades afterwards. The iceberg had been creeping forward starting in 2020, likely due to melting from below the waterline. And then, in late November 2023, the British Antarctic Survey said the iceberg was officially on the move. It’s currently heading out of the Weddell Sea and will enter into the Southern Atlantic, where, eventually, it’ll melt and disappear.
Space satellites are tracking the movement of the iceberg, including NOAA-21, a new weather satellite that just became operational this year. This satellite circles the globe 14 times a day in a polar orbit. NOAA-21 took the image of the iceberg above on December 7, 2023.
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As the iceberg enters warmer waters, it’ll undergo melting. Still, with an iceberg that’s almost 1,500 square miles (4,000 sq km), it won’t disappear overnight. About the iceberg’s progress, NASA said:
The berg became unstuck from the seafloor in the early 2020s … Past icebergs in this area eventually … entered the Drake Passage, a turbulent body of water between South America’s Cape Horn and Antarctica’s South Shetland Islands. From there, they typically move north toward the South Atlantic and quickly melt in the region’s warmer waters.
A23a hasn’t always been the title holder for world’s largest iceberg. One of the other icebergs to be crowned “world’s largest” was A-76. In 2021, this large iceberg calved from Antarctica’s Ronne Ice Shelf before breaking up. And before A-76, iceberg A-68 briefly took the title in 2017 before fracturing.
Watch the animation of iceberg A23a below as it moves over the course of a month below cloudy Antarctic skies.
Say hello to iceberg A23a, the largest iceberg in the world.
This extraordinary month-long time lapse captures its journey from the Weddell Sea into open ocean waters. pic.twitter.com/TEttjhxp4R
— CIRA (@CIRA_CSU) December 5, 2023
Bottom line: Weather satellites such as NOAA-21 are tracking the movements of the world’s largest iceberg, A23a, which is headed toward the South Atlantic.
The post World’s largest iceberg headed toward warm waters first appeared on EarthSky.
