Los Angeles-Sized Iceberg Avoids Major Collision In Antarctica

Satellite observations of the near-miss collision between A-74 and the Brunt Ice Shelf. Deep Chasm can be seen in the region. Image Credit: contains modified Copernicus Sentinel data (2021), processed by ESA, CC BY-SA 3.0 IGO

Iceberg A-74 broke off from Antarctica’s Brunt Ice Shelf back in March and since then it has been hanging about. Easterly winds in Early August started pushing the iceberg about and it came extremely close to a colossal collision.

In satellite radar images captured by the Copernicus Sentinel-1 mission, we can see the movement of the massive iceberg from August 9 to 18. The floating frozen chunk is 1,270 square kilometers (490.3 square miles), slightly smaller than Los Angeles. It passed very close to the western tip of Brunt and researchers were concerned that it might hit it.

The iceberg used to be the North Brunt and it is now A-74. Icebergs from the southernmost continent are named from the Antarctic quadrant in which they were originally sighted, then a sequential number. If the iceberg breaks apart then it also gets a sequential letter.

ice berg breaking apart
Satellite observations of the near-miss collision between A-74 and the Brunt Ice Shelf. Deep Chasm can be seen in the region. Image Credit: contains modified Copernicus Sentinel data (2021), processed by ESA, CC BY-SA 3.0 IGO

The entire region is of concern for glaciologists, as massive deep cracks have formed in the 150-meter (492-foot) thick ice shelf. If A-74 had hit the so-called West Brunt, it might have created an iceberg even larger than itself. The whole region is in an extremely delicate state and vast cracks can be seen in the satellite observations.

“The nose-shaped piece of the ice shelf, which is even larger than A-74 remains connected to the Brunt Ice Shelf, but barely. If the berg had collided more violently with this piece, it could have accelerated the fracture of the remaining ice bridge, causing it to break away. We will continue to routinely monitor the situation using Sentinel satellite imagery,” The European Space Agency's Mark Drinkwater said in a statement.

The situation got so worrying for such a long time that the British Antarctic Survey had to move its Halley VI Research Station inland to make sure that it would not be carried away in the formation of icebergs. The station is made up of eight interlinked pods on skis, so it was easily slid 20 kilometers (12 miles) away from the forming chasms.

It is currently winter in Antarctica which means darkness. Luckily, radar images don’t need sunlight to track changes to the ice. The Copernicus Sentinel-1 mission will continue to track the changes to this fragile region of Antarctica.

 
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