MASSIVE 490-SQUARE MILE ICEBERG BREAKS OFF FROM THICK ANTARCTIC SHELF

A giant 490-square mile iceberg broke away from the 492-feet thick Antarctic ice shelf near Britain's Halley research station. The 490-square mile iceberg is vaster than New York City, which measures just 306 square miles.

The iceberg broke down in a process called "calving", a natural occurrence caused by the forward motion of glaciers that eventually makes its end unstable. 

This comes almost a decade after scientists first detected vast cracks which formed in the ice shelf. These cracks are located in the Weddell Sea section of Antarctica.

The British Antarctic Survey (BAS) has been operating the research station since 2017. The team's first indication that at calving event was imminent was in November 2020, after a significant fracture, called the North Rift, carved its way through the ice. 

The rift continued to push northeast at up to 0.6 miles per day. On February 26, 2021, the crack widened, eventually splitting from the rest of the floating ice shelf. The examination of the iceberg's movement has been sent back to the research stations headquarters in Cambridge, England, for further studies.

NASA added that their research suggested the Brunt Ice Shelf crack was stable for nearly 35 years. Britain's Halley VI Research Station monitors the state of the enormous floating ice shelf daily. The team said that they had been preparing for the calving "for years". 

BAS director, Jane Francis, added, "Our teams at BAS have been prepared for the calving of an iceberg from Brunt Ice Shelf for years. We monitor the ice shelf daily using an automated network of high-precision GPS instruments that surround the station. These tools measure how the ice shelf is deforming and moving. We also use satellite images from ESA, NASA and the German satellite TerraSAR-X.

"All the data are sent back to Cambridge for analysis so we know what's happening. Even in the Antarctic winter, when there are no staff on the station, it's pitch black, and the temperature falls below minus 50 degrees C (or -58F)."

She continued, "Over the coming weeks or months, the iceberg may move away, or it could run aground and remain close to Brunt Ice Shelf. Halley Station is located inland, of all the active chasms, on the ice shelf connected to the continent. 

Our network of GPS instruments will give us early warning if the calving of this iceberg causes changes in the ice around our station."

Simon Garrod is the director of operations at the British Antarctic Survey. He stated that, about four years ago, they decided to move Halley Research Station more inland. This was to avoid it being carried away when an iceberg eventually formed. "That was a wise decision. Our job now is to keep a close eye on the situation and assess any potential impact of the present calving on the remaining ice shelf. We continuously review our contingency plans to ensure the safety of our staff, protect our research station, and maintain the delivery of the science we undertake at Halley."

Even though this iceberg may not be the largest one yet, it is the most extensive chunk that the Brunt Ice Shelf lost in more than 100 years since observations began in 1915.

An iceberg named the A68 broke off the Larsen C shelf back in 2017. A68 measured around 2,300 square miles. However, this iceberg did break up into separate pieces three years later. 

The world's most significant iceberg was named the B-15. This formed from Antarctica's Ross Ice Shelf back in 2000 and measured 4,200 square miles.