January 6, 2017

Iceberg the size of Delaware is about to break off from Antarctica

A massive iceberg, slightly smaller than the size of Delaware, appears ready to break free from the Larsen C ice shelf in the Antarctic Peninsula, according to the British Antarctic Survey.

Satellite images and other data from December 2016 revealed an expanding fracture in the ice shelf which indicates an iceberg with a region of up to 2,000 square miles is going to calve soon.

“The calving of this large iceberg could be the first step of the collapse of Larsen C ice shelf, which would result in the disintegration of a huge area of ice into a number of icebergs and smaller fragments,” David Vaughan, Director of Science at British Antarctic Survey, said in a news release.

The British Antarctic Survey scientists have a long-term study plan to observe ice shelves from both above and below to comprehend the reasons behind and ramifications of the rapid variations viewed in the area.

During this Antarctic research season, a glaciology study team has been on Larsen C using seismic tactics to survey the seafloor underneath the ice shelf. Because a calving event looks probable, the team hasn't camped on the ice, as is usual. As an alternative, they have made trips by aircraft from Rothera Research Station.

ice rift

This image, taken in November of 2016, shows the length of the rift (Credit: NASA)

Andrew Fleming, Remote Sensing Manager at British Antarctic Survey, noted that his team uses satellite imagery to create a comprehensive picture of the ice shelf.

“We use regular satellite images provided by the European Sentinel satellites to monitor cracks in the ice shelf,” Fleming said. “These images are perfect for following these changes since they provide detailed information, day or night and regardless of cloud cover.”

An ice shelf is a floating offshoot of land-based glaciers, which stream into the ocean. Since an ice shelf floats atop the ocean, its melting does not directly play a role in sea-level increase. However, ice shelves serve as mechanical supports, keeping glaciers from flowing all the way to the shore. The Larsen A and B ice shelves, which were located further to the north on the Antarctic Peninsula, folded away in 1995 and 2002, respectively. This triggered the spectacular acceleration of glaciers to their rear, with bigger volumes of ice coming into the ocean and adding to sea level rise.


Image credit: John Sonntag / NASA via E