In November 2023, the A23a mega iceberg set sail after being grounded on the ocean floor for well over 40 years. Now, driven by winds and currents, A23a is heading away from Antarctic waters as seen in this new animation.

The iceberg calved from West Antarctica in 1986 but quickly grounded itself in the Weddell Sea where it remained for over four decades. At around 4000 sq km in area, more than four times the size of New York City, and just over 280 m thick, the berg currently holds the title for world’s largest iceberg.

The animation uses sea-ice concentration data and shows the iceberg’s movements between 1 November 2023 to 23 January 2024. Similar to many icebergs originating from the Weddell sector, A23a is likely to be expelled into the Antarctic Circumpolar Current – propelling it towards the South Atlantic along a trajectory commonly referred to as ‘iceberg alley’.