SOURCE: Washington Post
DATE: Feb 26, 2021
SNIP: A large iceberg about 20 times the size of Manhattan broke off the Brunt Ice Shelf in the Weddell Sea section of Antarctica during the past day, following the buildup of a large crack in the floating ice during the past decade. The iceberg is about 490 square miles and about 492 feet thick, according to the British Antarctic Survey (BAS).
The iceberg is large, but not as huge as the iceberg that calved from the Larsen C Ice Shelf in 2017 and recently threatened to run aground on South Georgia Island.
The BAS maintains a research station on the ice shelf, known as the Halley Research Station, but it will be unaffected by this calving event, the organization said. In 2016, the BAS moved the station, which was built on skis, to protect it from spreading cracks that could’ve left it marooned, floating out to sea aboard an iceberg.
The past decade has seen three major cracks develop through the floating ice shelf, according to a BAS news release.
Ice shelves are floating areas of ice that help hold back ice anchored on land. Because they’re already displacing water, the calving event will not raise sea levels, but icebergs are carefully monitored in case they move into shipping lanes.
Adrian Luckman, a researcher at Swansea University, has closely tracked satellite images of Brunt as the cracks have progressed.
“Although the breaking off of large parts of Antarctic ice shelves is an entirely normal part of how they work, large calving events such as the one detected at the Brunt Ice Shelf on Friday remain quite rare and exciting,” he told the BBC.
Calving events can act to speed up the movement of inland ice into the sea, though it’s not clear that’s the case with the Brunt Ice Shelf in particular. Such movement would add to sea level rise, and there are growing concerns about the potentially unstoppable melting of the West Antarctic Ice Sheet from warming waters that are weakening ice shelves and penetrating the base of inland glaciers.