The iceberg started to crack off of Antarctica's Brunt Ice Shelf
The iceberg started to crack off of Antarctica's Brunt Ice Shelf in January 2021.
A massive iceberg broke off Antarctica's Brunt Ice Shelf, British researchers announced.

At 490 square miles, the berg is bigger than New York City, which is 302 square miles.

A crack in the ice shelf widened several hundred meters Friday before the iceberg sheared off. The last major chunk to come off in this area was in the early 1970s, the BBC said.

The event wasn't a surprise: "Our teams at the British Antarctic Survey (BAS) have been prepared for the calving of an iceberg from Brunt Ice Shelf for years," BAS director Jane Francis said in a statement.

The British Antarctic Survey's Halley Research Station is on the Brunt Ice Shelf. Glaciologists said the research station is unlikely to be affected by the calving event, which is what the breaking process is called.

The 12-person team working at the station left in mid-February, and the station is closed for the Antarctic winter.

"This is a dynamic situation," Simon Garrod, director of operations at the British Antarctic Survey, said in a statement. "Four years ago we moved Halley Research Station inland to ensure that it would not be 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."

Ice shelves are floating sheets connected to a landmass, according to the National Snow and Ice Data Center. Since the ice is already floating, the newly created iceberg won't contribute to rising sea levels.

The glaciological structure of this vast floating ice shelf is complex, the British Antarctic Survey said, and the impact of calving events is unpredictable.

There is no evidence that climate change played a significant role in this event, the BAS said. Calving is an entirely natural process wherever ice flowing on the land meets the ocean or large lakes.

Each year, 10,000 to 15,000 icebergs are calved worldwide, most of them on the small side, according to Canadian Geographic. The largest iceberg recorded calved off Antarctica in 2000: That one was about as big as the island of Jamaica.

As for what's going to happen to this iceberg, Francis said that "over the coming weeks or months, the iceberg may move away; or it could run aground and remain close to Brunt Ice Shelf."

As huge as it is, this iceberg is still dwarfed by the chunk of ice that broke off Antarctica's Larsen C Ice Shelf in 2017, which recently threatened to collide with South Georgia Island and is among the largest recorded at 2,240 square miles, Gizmodo said.