Right now, a big chunk of Antarctic ice is hanging on by a frozen thread.
British researchers monitoring the crack in the Larsen C ice shelf say that only about 12 miles now connect the chunk of ice to the rest of the continent.
"After a few months of steady, incremental advance since the last event, the rift grew suddenly by a further 18 km [11 miles] during the second half of December 2016," wrote Adrian Luckman in a statement Thursday by the MIDAS Project, which is monitoring changes in the area.
The crack in question has been growing for years, and is now a total of roughly 70 miles long. When the fissure reaches the far side of the shelf, an iceberg the size of Delaware will float off, leaving the Larsen C 10 percent smaller.
"This event will fundamentally change the landscape of the Antarctic Peninsula," Luckman wrote.
Ice shelves are important because they provide a buffer between the sea and the ice that sits on land, in this case on the Antarctic Peninsula. Without a healthy ice shelf, water from melting glaciers can flow straight to the sea, raising the sea level.