No one knows why trillion-ton Antarctic iceberg makes a full turn- headed for crash

Animation of the growth of the crack in the Larsen C ice shelf, from 2006 to 2017, as recorded by NASA/USGS Landsat satellites.
Animation of the growth of the crack in the Larsen C ice shelf, from 2006 to 2017, as recorded by NASA/USGS Landsat satellites. NASA/USGS Landsat

One of the largest ever icebergs on record, weighing in at over a trillion tons broke of the Larsen C ice shelf in July last year. The iceberg, called A68, is massive, it covers an area of 5,000 sq km and is about 350 metres thick. That is bigger than most cities in the world. This massive chunk of ice is now headed back toward Antarctica and is about to crash into the ice shelf from whence it came.

The iceberg was so massive, it spent the better part of a year simply stuck in the mud, in the sea floor, reports Earther. Now, in the middle of winter in that part of the world, the iceberg has made its biggest move since falling into the water. It has made a dramatic counter-clockwise spin and is headed toward the Larsen C shelf for a big crash.

According to ProjectMIDAS, an Antarctic research group, A68 is the sixth largest iceberg on record. Last year, as it broke off and fell into the ocean, the whole world watched with bated breadth, taking in every little piece of information about the shelf along the way. After the actual break and footage of it being released, the iceberg promptly got itself stuck on the ocean bed in a region called the Bawden Ice Rise, a shallow part of the sea where a berg of this size found itself grounded and unable to move.

Around July this year, one year later, the iceberg began to move. It was not readily seen as that part of the world remains under darkness in winter. A68 had started to drift north, notes the report. Mark Brandon, Polar oceanographer spotted this action using the brightness temperature data from the Suomi NPP satellite.

Data was then processed into false-colour images. Here, warmer regions like the ocean water are bright in comparison to the cooler icy surfaces like on the glaciers and icebergs. The images show A68 making a counter-clockwise turn in July, and by the end of August, the it completed a 90 degree rotation, placing itself perpendicular to the shelf.

As to what made A68 move, the report mentions that no knows as of now. One of the reasons why glaciologists are uncertain about this movement is because the sea bed in this region is not clearly mapped as yet, so predicting what will happen now, is not possible.