Iceberg set to break off Antarctica could calve

  • Between June 24 and 27, Larsen C Ice Shelf accelerated to more than 10m/ day
  • Scientists say outer edge of the still-attached iceberg is now at highest speeds 
  • While it’s unclear when exactly it will break off, it could be ‘days, hours, or weeks’ 

A massive chunk of an Antarctic ice shelf said to be hanging on by a thread has tripled in speed over the last few days – and now, scientists say the detachment of an iceberg the size of Delaware is imminent.

Between June 24th and 27th, the portion of the Larsen C Ice Shelf accelerated to more than ten meters per day.

While it remains attached as of now, scientists say calving could occur at any time, as the ‘soon-to-be-iceberg’ hits the highest speeds ever recorded.

A massive chunk of an Antarctic ice shelf said to be hanging on by a thread has tripled in speed over the last few days – and now, scientists say the detachment of an iceberg the size of Delaware is imminent. The increase in speed can be seen in the image above 

A massive chunk of an Antarctic ice shelf said to be hanging on by a thread has tripled in speed over the last few days – and now, scientists say the detachment of an iceberg the size of Delaware is imminent. The increase in speed can be seen in the image above 

LARSEN C, FINAL DAYS

Researchers have been monitoring a huge crack in the Antarctic ice shelf.

The rift grew suddenly by around 18 kilometres (11 miles) in December 2016, leaving a vast iceberg more than 5,000 square kilometres (1,900 square miles) ‘hanging by a thread’.

The main rift continued to grow early this year and satellite data revealed a second branch of the rift, some nine miles (15 km), was moving towards the edge of the ice.

In the largest jump since January, the rift grew an additional 10 miles (16 km) between May 25 and May 31.

Researchers have warned that it is   now very close to calving.

For several months, the growing rift in Larsen C has been threatening to release more than 10 percent of the ice shelf’s area.

When it finally does break off, it will dramatically change the landscape of the Antarctic Peninsula, the experts say.

The iceberg itself won’t cause sea levels to rise.

But, if the shelf breaks up further, it could spur glaciers that flow off the land toward the ocean, which would affect sea levels, the team explained earlier this year.

For now, satellite images taken just after midnight June 28th show that the iceberg is still attached.

The recent acceleration, however, suggests its calving could happen any day now.

‘The iceberg remains attached to the ice shelf, but its outer end is moving at the highest speed ever recorded on this ice shelf,’ according to the experts with Project MIDAS, who have been investigating the ice shelf.

‘We still can’t tell when calving will occur, it could be hours, days or weeks – but this is a notable departure from previous observations.’

At the beginning of this month, the researchers noted that the ice chunk is ‘very close’ to finally calving off and producing one of the biggest icebergs ever recorded.

For several months, the growing rift in Larsen C has been threatening to release more than 10 percent of the ice shelf’s area. When it finally does break off, it will dramatically change the landscape of the Antarctic Peninsula, the experts say

For several months, the growing rift in Larsen C has been threatening to release more than 10 percent of the ice shelf’s area. When it finally does break off, it will dramatically change the landscape of the Antarctic Peninsula, the experts say

RECORD ICEBERGS 

The largest icebergs known have all calved from ice shelves. 

In 1956, a huge iceberg of roughly 32,000 km² – bigger than Belgium – was spotted in the Ross Sea by a US Navy icebreaker. 

However, since there were no satellites in orbit at this point, its exact size was not verified. In 1986, a section of the Filchner ice shelf roughly the size of Wales calved – but this iceberg broke into three pieces almost immediately. 

The largest iceberg recorded by satellites calved from the Ross ice shelf in 2001, and was roughly the size of Jamaica at 11,000 km².

 

Researchers have been monitoring the huge crack, which began to spread rapidly in December 2016 and has continued ever since.

In the largest jump since January, the rift in the Larsen C Ice Shelf grew an additional 10 miles (16 km) by the end of May, over the course of a few weeks.

Researchers from Swansea University say that the crack grew between May 25 and May 31, the last two dates that the the European Space Agency’s Sentinel-1 satellites passed overhead.

At the time, images showed that the crack in the Antarctic ice had reached almost 125 miles (200km) long.

The tip of the rift also appears to have rapidly changed direction, turning towards the ice front, which suggests that it is very close to calving, leaving just eight miles (13 km) of ice between it and the sea.

Once the calving happens it will lose around 10 per cent of its area, creating an iceberg roughly the same size as South Wales or Delaware.

Researchers have been monitoring the huge crack, which began to spread rapidly in December 2016 and has continued ever since

Researchers from Swansea University say that the crack grew between May 25 and May 31, the last two dates that the the European Space Agency's Sentinel-1 satellites passed overhead

Researchers from Swansea University say that the crack grew between May 25 and May 31, the last two dates that the the European Space Agency’s Sentinel-1 satellites passed overhead

Speaking to the BBC, Swansea University Professor Adrian Luckman said: ‘The rift has propagated a further 16km (ten miles), with a significant apparent right turn towards the end, moving the tip 13km (eight miles) from the ice edge.’

The rift in the Larsen C Ice Shelf grew suddenly by around 18 kilometres (11 miles) in December 2016, leaving a vast iceberg more than 5,000 square kilometres (1,900 square miles) ‘hanging by a thread’.

The main rift continued to grow early this year and satellite dadita revealed a second branch of the rift, some nine miles (15 km), was moving towards the edge of the ice.

Researchers have warned the ice shelf will be less stable after the iceberg calves, and could follow the example of its neighbouring ice shelf Larsen B, which completely disintegrated in 2002 after a similar event. 

 


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