The iceberg that broke away from Antarctica sometime between Monday and Wednesday is one of the largest ever observed.

NASA MODIS thermal image from July 12 2017. With size reference to Wales.

As previously reported, the large crack observed in 2016, that continued to spread have now finally broken of the Antarctic continetal sea ice.

NASA Suomi VIIRS panchromatic image from July 12 2017, confirming the calving.

The giant iceberg – half the size of Jamaica – was released into the ocean sometime between Monday, July 10 and Wednesday, July 12, according to the scientists continually observing the process – confirmed by a US satellite passing by on Wednesday.

The iceberg was part of the ice shelf Larsen C, is about 6,000 square kilometers. Leaving Larsen C ten percent smaller than before.

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

An ice shelf is a thick floating platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto the ocean surface.

The Larsen C ice shelf if believed to act as a plug in front of the glacier Larsen C, and the risk has therefore increased that more ice will slide into the sea.

The iceberg isn’t the largest ever observed, however, known as the A68, it is about half the size of the world record holder B-15, which broke away from the ice shelf Ross in 2000.

Reference:

Project Midas: Larsen C calves trillion ton iceberg
ESA: Copernicus Sentinel-1 mission