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Antarctic iceberg has dramatic close shave with unstable ice shelf

Strong winds caused the massive A-74 iceberg to brush up against the Brunt Ice Shelf.

Amanda Kooser
Freelance writer Amanda C. Kooser covers gadgets and tech news with a twist for CNET. When not wallowing in weird gear and iPad apps for cats, she can be found tinkering with her 1956 DeSoto.
Amanda Kooser
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This satellite view shows the movement of the A-74 iceberg as winds pushed it around the Brunt Ice Shelf in Antarctica earlier this month.

Contains modified Copernicus Sentinel data (2021), processed by ESA

Earlier this year, a jumbo iceberg calved from the Brunt Ice Shelf in Antarctica. Researchers had been waiting for it to break free after years of cracks spreading across the area. That iceberg, dubbed A-74, lingered near where it broke away until this month when winds gave it a shove, sending it twirling around a peninsula of the ice shelf. 

The European Space Agency shared a series of satellite images from Aug. 9 to Aug. 18 showing the iceberg's movement and its dramatic brush with the shelf.   

A-74 is about the size of Los Angeles, and it could have packed quite a wallop if the hit on the ice shelf had been more direct. The impact could have led to the creation of a new, more massive iceberg. For once, though, there is no catastrophe afoot, so this is mostly about the wow factor of witnessing the southernmost continent in action.

"The nose-shaped piece of the ice shelf, which is even larger than A-74, remains connected to the Brunt Ice Shelf, but barely," Mark Drinkwater, head of ESA's Earth & Mission Science Division, said Friday in a statement. "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."     

The ice shelf has been unstable for quite some time. In 2016 and 2017, the British Antarctic Survey relocated its Halley VI Research Station to protect the station and the scientists using it. The station, made up of eight pods, can be "easily moved" because it's built on skis, ESA said.

The Copernicus Sentinel-1 satellite shot the harrowing views of A-74's movement. 

"During the dark winter months in Antarctica, radar images are indispensable because, apart from the Brunt Ice Shelf being in a remote region, radar continues to deliver images regardless of the weather or seasonal darkness," ESA said.

According to British Antarctic Survey, Brunt's iceberg activity is a natural process and there's no evidence of climate change playing a significant role.

Researchers will continue to monitor A-74 and the Brunt Ice Shelf. It might not be too long before another, even bigger iceberg makes its escape.