The 490-square mile iceberg broke away from the Brunt Ice Shelf about a decade after scientists started detecting cracks in the ice, wrote the British Antarctic Survey (BAS) in a statement. New York City is roughly 302 square miles.
“Our teams at BAS have been prepared for the calving of an iceberg from Brunt Ice Shelf for years,” said Professor Dame Jane Francis, Director of British Antarctic Survey.
The first indication that the glacier would break off occurred in November when a new chasm – called North Rift – headed toward another large chasm about 20 miles away. In January, the rift pushed northeast at more than half a mile each day, cutting through the 490-foot thick floating ice shelf.
The iceberg formed after the crack widened on the morning of Feb. 26, “releasing it from the rest of [the] floating ice shelf,” according to the BAS.
The BAS monitors the ice shelf daily using an automated network of high-precision GPS instruments surrounding Halley Research Station, which measures how the ice shelf is deforming and moving, Francis said. The teams also use satellite images from ESA, NASA, and the German satellite TerraSAR-X.
“Halley Station is located inland of all the active chasms, on the part of the ice shelf that remains connected to the continent,” said Francis. “Our network of GPS instruments will give us early warning if the calving of this iceberg causes changes in the ice around our station.”
The 12-person team left Halley Research Station early last month, which is now closed for the Antarctic winter. The station was safe from the break since it relocated inland in 2016 to avoid the paths of two chasms — named “Chasm 1” and “Halloween Crack.”
Francis added that in the coming weeks or months, the iceberg may move away, or aground and remain close to the Brunt Ice Shelf.
“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,” said Simon Garrod, Director of Operations at BAS. “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.”
Researchers said there is no evidence that climate change played a significant role in the event.
“Change in the ice at Halley is a natural process and there is no connection to the calving events seen on Larsen C Ice Shelf,” according to the BAS.