A massive iceberg has broken off the Brunt Ice Shelf in Antarctica, just 12 miles (19 km) from where British scientists work at a research station.
The iceberg is 490 feet (150 meters) thick and 600 square miles (1,550 square kilometers) in area – roughly the size of Greater London.
It collapsed at a huge crack that split the ice shelf, known as Chasm-1, which has been growing about 2.5 miles (4 kilometers) every year since 2012.
GPS sensors began picking up motion on Chasm-1 between 7 p.m. and 8 p.m. Sunday, when it extended nearly 40 miles (60 kilometers), across the entire shelf.
The glacier broke at a huge crack that cleaved the ice shelf, known as Chasm-1 (pictured), which has been growing about 2.5 miles (4 km) every year since 2012
GPS sensors began picking up motion on Chasm-1 between 7 p.m. and 8 p.m. Sunday, when it extended nearly 40 miles (60 km) — across the entire shelf.
Fortunately, all 21 staff working at Halley Research Station with the British Antarctic Survey (BAS) were completely safe, and were preparing for this eventuality.
Professor Dame Jane Francis, Director of BAS, said: ‘Measurements of the ice shelf are made several times a day using an automated network of high-accuracy GPS devices that surround the station.
This measures how the ice shelf deforms and moves, and compares to satellite images from ESA, NASA and the German TerraSAR-X satellite.
All the data is sent back to Cambridge for analysis, so we know what’s going on even in Antarctic winter – when there’s no crew on station, it’s dark for 24 hours and the temperature drops below -58 degrees Fahrenheit (- 50 degrees Fahrenheit (degrees Celsius).
Glaciologists confirmed that the area of ice on which the station is located remains unaffected by the event.
In 2016, the continued growth of Chasm-1 prompted BAS — the National Institute for Polar Research — to move the site 14 miles (23 kilometers) inland.
Chasm-1 (pictured) had been dormant for 25 years before 2012, when satellite observations revealed that it had begun to move
While this wouldn’t be the largest iceberg to break off from Antarctica, it is the largest chunk lost by the ice shelf since observations began more than 100 years ago in 1915. Pictured: Chasm-1
The birthing event over the weekend was completely natural—and not at all related to climate change—and caused by the spring tide. Calving is a natural occurrence caused by the forward motion of a glacier making its end unstable
The birthing event over the weekend was completely natural—and not at all related to climate change—and caused by the spring tide.
Professor Dominic Hodgson, BAS glaciologist, said: ‘This calving event was expected and is part of the normal behavior of the Brunt Ice Shelf.
“Our science and operational teams continue to monitor the ice shelf in real time to ensure its safety, and to keep delivering on the science we’re doing at Halley.”
Calving is a natural occurrence caused by the forward motion of a glacier making its end unstable.
During a calving event, part of the end of a glacier falls off, often forming an iceberg.
The Halley VI Research Center (pictured) is an internationally important platform for atmospheric and space weather monitoring in a climate-sensitive region
It sits on the Brunt Ice Shelf, which floats in the frozen continent and flows at a rate of 1.5 miles a year.
Staff are deployed to the station between November and March to maintain facilities that allow them to monitor experiments remotely during the winter
While this wouldn’t be the largest iceberg to break off from Antarctica, it is the largest chunk lost by the ice shelf since observations began more than 100 years ago in 1915.
Chasm-1 had been dormant for at least 35 years before 2012, when satellite observations revealed that it had begun to move.
In 2015 and 2016, scientists used ice-penetrating radar techniques and satellite imagery to determine which path the fracture could take and how fast it could grow.
By December, Chasm-1 was cutting through most of the ice shelf, marking the beginning of the calving event.
The iceberg it formed, which will be named by the US National Ice Center, is expected to drift in the Weddell Sea, but glaciologists will track its movement.
The Halley VI Research Center is an important international platform for atmospheric and space weather monitoring in a climate-sensitive region.
It has been vacant for the past six winters due to a complex ice situation that makes the impact of birth events unpredictable.
However, staff are deployed there between November and March to maintain facilities that allow them to monitor experiments remotely during the winter.
The aircraft currently at the site are scheduled to gather around February 6.
The Brunt Ice Shelf is formed from glacial ice that flowed from land in Antarctica and floated into the sea.
All 21 staff working at Halley Research Station (pictured) with the British Antarctic Survey were completely safe, and were preparing for the eventuality
This is Brunt Ice Shelf’s second major birth in the past two years, with the first occurring in February 2021.
In November 2020, A large fracture—called the North Rift—began to cut its way through the ice and continued to expand through the start of the new year.
This has built up into a 490-square-mile (1,270 sq km) iceberg, called A74, which splits off into the vast floating ice shelf and drifts into the Weddell Sea.
The Brunt Ice Shelf is formed from glacial ice that originally fell as snow on Antarctica and flowed from the land into the sea.
It flows at a rate of up to 1.2 miles (2 km) per year westward toward the sea where it swells at irregular intervals from icebergs.
In 2021, an iceberg roughly 500 square miles in size passed the western Brant ice shelf, but did not split Chasm-1.
There was concern that if it hit West Brunt too hard, it would eventually cause the block to break away from the main ice shelf and create a new iceberg.
