by Lasse Rabenstein on 2017-10-13
After a long journey, four gigantic icebergs have finally reached the open waters north of the Antarctic Peninsula. Each of the four icebergs are approximately 50 km in length. Nevertheless, they are only fragments of yet larger icebergs which calved between 1987 and 2010. The question is where they float next, when will they break apart, and will they remain in these waters until the Antarctic expedition cruise season starts?
The four icebergs are named B15-t, B15-z, B09-f, and C28-b, according to the US National Ice Center naming convention and iceberg data base . The two B15 icebergs are remnants of the once largest free-floating iceberg ever recorded: the B15 iceberg which broke off the Ross Sea Shelf ice in March 2000. Over the years B15 broke into smaller pieces, hence the suffixes a-z in the fragment names. Parts of B15 travelled around the whole of eastern Antarctica, crossed the Weddell Sea and now drift in the open sea north of the Antarctic Peninsula.
B09 is even older and has been wandering in the Antarctic region since 1987. It is the longest monitored iceberg ever. After its calving and first drift period B09 had a long rest for 18 years in the eastern Antarctica near the Mertz glacier. In 2010 it started to move again and collided with the floating Mertz glacier tongue. That was the birth of the fourth iceberg mentioned above: C28. Since then, two large fragments of B09 and C28 have travelled together anti-clockwise around Antarctica. On their way C28 almost extinguished a colony of penguins by blocking the bay where the colony is located. Similarly to the two B15 fragments they passed the Weddell sea this year and are now located in the open sea north of the peninsula.
Although such gigantic icebergs look frightening - and beautiful at the same time - they are hard to miss for the nautical crew on board a cruise ship. They can be easily avoided. But what happens when such icebergs break into smaller fragments? Small icebergs, which hardly break the water surface, are much more difficult to handle and can be easily missed. Remember: only about 10% of a free-floating iceberg is visible above the surface. Icebergs are dynamic and will break apart at some point. Therefore ships are well advised to keep a safe distance to these large objects. Any ship operating in the region should have up to date information on board about the location of these large icebergs. The Drift Noise operational ice maps product ensures that all images provided by the NASA, ESA, and JAXA satellite missions are available on board.