Giant iceberg A23a begins drifting from Antarctic waters after decades

Filchner Ice Shelf in Antarctica

27th November 2023 – (London) The British Antarctic Survey has reported that one of the world’s largest icebergs, known as A23a, is now drifting beyond Antarctic waters after being grounded for over 30 years. This massive iceberg broke away from the Filchner Ice Shelf in Antarctica back in 1986 but remained trapped on the ocean floor within the Weddell Sea.

With a size approximately three times that of New York City and more than double the size of Greater London, measuring around 1,500 square miles, A23a has finally started to move. Andrew Fleming, a remote sensing expert from the British Antarctic Survey, revealed to the BBC on Friday that the iceberg has been slowly drifting over the past year. However, it has recently gained momentum and is now passing the northern tip of the Antarctic Peninsula, aided by wind patterns and ocean currents.

When discussing the reasons behind the iceberg’s movement, Fleming explained, “I asked a couple of colleagues about this, wondering if there was any possible change in shelf water temperatures that might have provoked it, but the consensus is the time had just come.” He further elaborated, stating, “It was grounded since 1986, but eventually it was going to decrease (in size) sufficiently… to lose grip and start moving.”

Fleming first observed signs of movement from A23a in 2020. The British Antarctic Survey confirmed that the iceberg has now become dislodged and is being carried along by ocean currents towards the sub-Antarctic region of South Georgia.