An enormous iceberg estimated to be almost the size of Los Angeles recently broke off the 150-meter-thick (500 feet) Brunt Ice Shelf in Antarctica. Now new high res images taken by the UK satellite Vision-1 and acquired by Airbus for the British Antarctic Survey (BAS) reveal details less than 1 meter around the large crack that led to the break-off event.
Glaciologists from the BAS Halley Research Station working in the area have been anticipating the calving event for at least the last decade and saw the first signs of things starting to escalate back in November 2020.
The Brunt Ice Shelf, which borders the Antarctic coast of Coats Land, has been at major risk of iceberg break-offs due to the formation of several chasms over the years. When researchers noted that a newly formed chasm in the North Rift about 23 kilometers (14 miles) from the Halley Research station started to move closer to another large crack in the Stancomb-Wills Glacier Tongue, just 35 kilometers (22 miles) away, they knew it was only a matter of time until a huge break-off would occur.
The video below shows the size of the North Rift, taken on February 16, 2021.
As the cracks widened, an iceberg dubbed A74 eventually broke away from the Brunt Ice Shelf on February 26, setting free a floating chunk of ice with an area of 1,270 square kilometers (490.3 square miles).
The images showcase the North Rift in the ever-widening gap on February 27, 2021, a day after the carving event took place.
The BAS researchers will continue to use images from Vision-1 to investigate the future trajectory of A74 as another collision might be imminent that could see A74 collide with the western part of the Brunt Ice Shelf, which would result in a further calving event closer to the currently unoccupied (due to winter) Halley Research Station.
Icebergs are generally closely monitored, with NASA also keeping an eye on events. Although break-offs are considered a normal part of the Antarctic recycling of snow and ice, some are driven by the warming climate and increasing temperatures of the oceans. Hence a lot of work goes into understanding how these large objects move and go on to melt further after they break off from an ice shelf or glacier.
Interestingly, recent findings revealed that icebergs are in fact melting faster than current models suggest and that the shape of the iceberg may be important to how fast this occurs. Icebergs narrow in shape melt faster than those that are broader and shallower, the new findings suggest.
On a slightly more fun note, if you have ever wondered how the shape of an iceberg might impact its ability to stay afloat in water, you can find out yourself with a new interactive website that allows you to draw your very own iceberg and see whether your shape stays afloat. Give it a try here, we promise it is a lot of fun.