Glaciers have been expecting this kind of event for a decade.
An iceberg larger than New York City has broken an ice shelf in Antarctica, scientists say.
The research organization announced that the 490-square-kilometer glacier had broken off from the Brunt Ice Shelf, where the British Antarctic Survey’s Halley Research Station is located. New York City is about 302 square miles.
Glaciers have been expecting a major calving event for at least a decade, according to BAS. The first indication that the glacier would break was in November, when a new gorge called North Rift – the third major rift that became active in the ice shelf in the last ten years – was on its way to another gorge about 20 km away.
The rift then began pushing more than half a mile a day in January and cutting through the 490-foot ice shelf, scientists said. The iceberg formed when the rift widened on February 26 and released it from the ice shelf.
“Our teams at BAS have been preparing for years for calving an iceberg from the Brunt Ice Shelf,” said Jane Francis, director of the British Antarctic Survey Dame.
The BAS monitors the ice shelf daily using an automated network of high-precision GPS instruments that surround the station, which measures how the ice shelf deforms and moves. Satellite images from the European Space Agency, NASA and the German satellite TerraSAR-X are also being used, Francis said.
The impact of the calving event on the ice shelf is unclear, scientists said. In the coming weeks or months, the iceberg could move away or walk on the beach and stay close to the ice shelf, Francis said.
The BAS research station is currently closed for the Antarctic winter and is unlikely to be affected by the calving event, scientists said. The BAS said the station was moved further inland in 2016 to avoid the tracks of two gorges named ‘Chasm 1’, which was formed in 2012, and the ‘Halloween Crack’, which was formed in 2016. None have grown in the last 18 months.
The British operations director of the Antarctic survey, Simon Garrod, said in a statement that the relocation of the station was a ‘wise decision’.
“Our job now is to keep a close eye on the situation and assess the possible impact of the current calving on the remaining ice shelf,” Garrod said. “We are constantly reviewing our emergency plans to ensure the safety of our staff, protect our research station and maintain the delivery of the science we undertake in Halley.”
Staff have only been working at the BAS Antarctic station during the summer since 2017 due to the difficult evacuation during the dark winter months, when the air is pitch black.