Earlier this month, researchers warned a 2,000-square-mile chunk of ice was perilously close to breaking away from Antarctica after a major crack in the Larsen C ice shelf grew more than 10 miles in December. Now, that crack has grown even bigger, scientists say. Another massive expansion has left just 12 miles of ice holding a Delaware-sized iceberg from breaking off the continent.

Researchers with Project MIDAS, a British initiative to track the effects of climate change on the Larsen C shelf, said on Thursday that the crack grew an additional 6 miles in the first three weeks of January, based on recent satellite images. The ice shelf is the northernmost major ice sheet in Antarctica.

Project MIDAS An image released by Project MIDAS shows the expansion of the crack in recent months.

“When it calves, the Larsen C Ice Shelf will lose more than 10% of its area to leave the ice front at its most retreated position ever recorded,” Adrian Luckman, the lead researcher behind the MIDAS Project, said in a post. “This event will fundamentally change the landscape of the Antarctic Peninsula.”

While the calving of the ice shelf wouldn’t directly contribute to sea level rise (the ice is already floating on top of the water, like ice in a glass), scientists say the collapse could trigger the melting of land ice the Larsen C is currently holding back.

Luckman previously told the BBC he’d be “amazed” if the ice shelf didn’t break away in the next few months, saying: “It’s so close to calving that I think it’s inevitable.”

NASA Earth Observatory An image released by NASA in November of the rift in the Larsen C.

While he noted such predictions are hard to make, in an interview this week he told the outlet the rapid expansion of the crack may portend a quick demise for the section of the shelf, which would create one of the largest icebergs in recorded history.

“My feeling is that this new development suggests something will happen within weeks to months, but there is an outside chance that further growth will be slow for longer than that,” Luckman said.

Two sister ice shelfs in the region, the Larsen A and Larsen B, have already been cleaved from Antarctica in dramatic fashion, in 1995 and 2002, respectively. The Larsen B’s demise was captured in a spectacular video released by NASA that shows the sheet disintegrating into the ocean.