Remained stranded near the coast since 1986, the huge iceberg A23a had almost become an ice marker in Antarctica. But this enormous block of 3,900 km² has finally begun its drift towards the North, which will mark its end, unless it runs aground again. Despite its size, it does not really pose any danger…
Although it is definitely a giant (almost half the size of Corsica) and the largest in the world today, the A23a iceberg is not the largest to have ever traveled the oceans. However, this one is particularly well known and identified. To understand this, you have to go back four decades! The Soviet Union then had a base on the Antarctic ice shelf of Filchner, Druzhnaya 1. Bad luck, in 1986 the USSR had to evacuate and dismantle the installation quickly: it was on what would be called A23a, a huge iceberg which begins to drift in November 1986, in the austral spring.
But surprisingly enough, this one didn’t go very far. Its ice crust, almost 400 meters thick, was blocked in 1986 in a silty shoal in the Weddell Sea. And for almost 37 years, A23a formed like an ice island. However, there is no point in putting it on the maps, because in 2023, it has definitively detached itself to (finally) follow the currents towards the North and leave Antarctica.
Why did he set out again?
If there is no real scientific explanation for this change after 37 years of relative immobility, satellite radar monitoring has made it possible to note an evolution and a drift of a few kilometers on the bottom from 2020. Now, A23a is engaged on what some call “the alley of the icebergs”: carried by the currents, it heads lazily towards Elephant Island and South Georgia.
On its route, it is not really dangerous for modern ships which are equipped with radars, especially since even with the naked eye, it is difficult to miss this almost rectangular block of ice measuring 50 kilometers on a side! In any case, despite its dimensions and its impressive mass, if it does not run aground, it should follow the currents and melt gently in the months and years to come, circling the white continent and the southern lands.
Iceberg to follow!
The formation of icebergs is natural when the seas warm up, which is the case locally every spring, in the North as in the South, so the inevitable question of climate change does not necessarily come into account here. Several studies have even shown the beneficial contribution of this type of large iceberg to the fauna and flora of the oceans, because they help to spread minerals and nutrients in their wake… even if they can also have devastating effects.
Indeed, there is some fear that with its size A23a, if it runs aground along South Georgia (it is a little larger than the island) or Elephant Island (it is much larger larger than the group of islands), prevents access to penguin nesting areas, or hunting areas for several groups of local predators. Until then, it won’t be too difficult to follow!
Source : BBC
1