A rift in Antarctica that has grown substantially in 2017 may lead to one of the largest icebergs ever recorded.

The latest satellite data shows that the rift in the Larsen C ice shelf in Antarctica has grown 10 kilometers (km) since the new year, bringing the total to 175 km.

Professor Adrian Luckman of Swansea University College of Science in the U.K., explained the threat the rift is causing.

“We can report a further extension of the rift which threatens to calve an iceberg measuring more than 5,000 sq. km in area from the Larsen C Ice Shelf,” Larsen said in a statement.

The rift has grown parallel to the shelf edge, meaning that the 5,000 square km iceberg remains attached by only about 20 km of ice.

“If it doesn’t go in the next few months, I’ll be amazed,” Luckman said. “There hasn’t been enough cloud-free Landsat images but we’ve managed to combine a pair of Esa Sentinel-1 radar images to notice this extension, and it’s so close to calving that I think it’s inevitable.”

When it calves, the ice shelf will lose more than 10 percent of its area, leaving the ice front at its most retreated position ever recorded.

This is expected to fundamentally change the landscape of the Antarctic Peninsula.

Luckman estimated that when the area breaks apart it will be about 5,000 sq. km, which would be among the 10 biggest icebergs ever recorded.

Larsen C is approximately 350 meters thick and floats on the seas at the edge of West Antarctica, holding back the flow of glaciers that feed into it.

Researchers have been tracking the rift for several years following the collapse of the Larsen A ice shelf in 1995 and the disintegration of Larsen B seven years later, following a similar rift-inducing calving event.

 “We are convinced, although others are not, that the remaining ice shelf will be less stable than the present one,” Luckman said. “We would expect in the ensuing months to years further calving events and maybe an eventual collapse but it’s a very hard thing to predict and our models say it will be less stable; not that it will immediately collapse or anything like that.”

Last year Project MIDAS—a U.K.-based Antarctic research project charged with investigating the effects of a warming climate on the Larsen C ice shelf—reported that the rift was growing fast.

However, in December the rift began to grow even further by 18 km in just a few weeks.

According to Luckman, the rift is a geographical event and not a climate event, although climate warming may have brought forward the likely separation of the iceberg.

According to estimates, if all the ice that the Larsen C shelf currently holds back entered the sea, global waters would rise by 10cm.

The MIDAS Project will continue to monitor the development of the rift and assess its ongoing impact on the ice shelf.