After 22 years, iceberg B-22A starts its journey around Antarctica | Polarjournal
Iceberg B-22A broke off the Thwaites Glacier in 2001/02 and remained only about 100 km offshore. The iceberg was and remained so big that it was even visible on Google Maps all these years. Map: Google Maps

When massive icebergs break off in Antarctica, they usually drift out into the open sea and are then driven around the continent by currents and winds. But every now and then huge ice blocks get stuck on the seafloor and have to melt a bit before they start their journey and drift towards their end. However, an iceberg on the well-known and important Thwaites Glacier in West Antarctica took a lot of time to break away from Antarctica.

For more than 22 years, iceberg B-22A had been stuck in its place off the Antarctic coast and had left its mark on the coastal landscape. Now it has broken away from its mooring and is drifting into the Amundsen Sea, where it is expected to drift along the coast by the currents and winds, slowly but surely breaking apart and melting away. The process of drifting loose was recorded by NASA’s Terra and Aqua satellites using on-board MODIS equipment.

Between October 2022 and March 2023, the iceberg broke away from its site and slowly drifted toward the open sea. In the end, it had already covered around 175 km in just a few months. Video: NASA Goddard Space Flight Center

NASA experts had discovered on satellite images taken between Oct. 24, 2022, and March 26, 2023, that the iceberg had broken away from where it had been stuck since 2012. Thanks to its size of about 3,000 square kilometers, the iceberg was also clearly visible on all kinds of satellite images during the whole time. Currently, darkness now prevails in the region, but thanks to some equipment, the path of the iceberg can still be followed.

The fact that icebergs take several years to drift from their starting point into the open sea has long been known and is related to the size of the iceberg and the topography on the Antarctic coast. Often, the icy colossi get stuck on underwater obstacles and slowly melt before traveling further. But B-22A, at about 22 years old, has reached a biblical age for a berg in the same place. Christopher Shuman, a glaciologist at the University of Maryland and an expert at NASA, agrees. In his opinion, conditions in the Amundsen Sea with cold deep currents and little movement in previous years have had little effect on the iceberg.

Research teams have discovered several times that warmer deep waters are now flowing into the region from the north as well, slowly melting everything icy from below. Since the iceberg had also acted like a cork, holding back some of the ice masses lying between it and the coast, it will now be exciting for the Thwaites teams to observe whether or not there will be any movement in the ice masses. At least for the moment, however, it should remain quiet, because for the time being winter keeps things calm on the coast. For B-22A, however, its long migration now begins, ever further away from Antarctica towards the north and its melting end.

Dr Michael Wenger, PolarJournal

More on the topic

Print Friendly, PDF & Email
error: Content is protected !!
Share This