Publication Date April 4, 2017

The massive crack in the Antarctic ice shelf is hanging on by a 12-mile 'thread'

A close-up view of the crack, or rift, in Antarctica's Larsen C ice shelf, as seen on Nov. 10, 2016. Photo: NASA Goddard Space Flight Center

One of the world's biggest icebergs ever is poised to break off from an Antarctic ice shelf, but scientists say it's still hanging on by a 12-mile "thread."

They also aren't sure when the now 110-mile crack will finally break open the rest of the way, creating a massive iceberg larger than Rhode Island. "It is particularly hard to predict when it will occur," said Adrian Luckman of Project MIDAS, a British Antarctic research project that's keeping watch on the ever-growing crack.

"I am quite surprised as to how long it is holding on!" he said in an e-mail to USA TODAY.

The crack in the Larsen C Ice Shelf is more than 1,000 feet wide and has grown by 50 miles since 2011, according to the British Antarctic Survey. Once the crack goes all the way across, the iceberg will break off.