A huge iceberg just broke off of one of the most fragile glaciers in Antarctica.
The chunk of ice, about the size of the Tampa, Florida, cleaved from the Pine Island Glacier in West Antarctica. Scientists had been keeping an eye on two huge cracks in an ice shelf down there for months. Now, the berg is finally floating freely.
As it cleaved off its ice shelf, the iceberg broke into pieces, creating a bunch of smaller, floating ice hunks.
Calving events, the term for a large iceberg breaking off from an ice shelf, have become more and more common. Scientists are growing increasingly worried about the integrity of the glaciers behind them.
This iceberg alone won’t raise sea levels: Even before it broke off, it was floating on water. But it was buttressing the Pine Island Glacier, acting as a barrier between the warmer sea water and the ice that makes up the glacier.
As more ice floats off into the ocean, that could lead to a runaway disintegration of Antarctica’s glaciers, allowing water to eat away at glaciers from the bottom. There’s enough “vulnerable ice” in the West Antarctic region, between the Pine Island and Thwaites glaciers, to fuel up to four feet of sea level rise, according to NASA.
This berg’s been threatening to fall off its ice shelf for over a year. European Space Agency satellites noted that a pair of cracks in the ice that it’d been monitoring had grown to a length of more than 12 miles back in October.
Over the weekend, the iceberg finally made a run for it.
Even under normal circumstances, glaciers in Antarctica slough off ice into the ocean. But before the world started to heat up as dramatically as it has, calving events like this one would happen once every four years or so. Now they’re virtually an annual occurrence.
Parts of Antarctica are warming faster than the rest of the world, and the melting of ice sheets there scientists think represent one of the first signs of irreversible climate change, according to UN scientists. It was T-shirt weather down there last week — a record-breaking, balmy 65 degrees Fahrenheit.
The Pine Island iceberg is one of several big ‘bergs that scientists have been watching closely on the rapidly-warming southern continent.
An iceberg twice the size of New York City is expected to drop off the Brunt Ice Shelf any day now, just as soon as two cracks in the ice intersect.
Another one, the largest ever recorded — about the size of the state of Delaware — has been stuck off the coast of the Antarctic Peninsula, it’s bottom apparently stuck to the ocean floor. As it cracks into smaller pieces, it might break loose.
Its expected path will draw it north, on a route that’s now referred to as “Iceberg Alley.”
Cover: In this June 17, 2016 file-pool photo, a fisherman drives a boat during then-Secretary of State John Kerry's tour of the Jakobshavn Glacier and the Ilulissat Icefjord, located near the Arctic Circle in Ilulissat, Greenland. The National Oceanic and Atmospheric Administration on Thursday, Aug. 10, 2017, released its annual state of the climate 2016 report, highlighting numerous records including hottest year, highest sea level and lowest sea ice in the Arctic and Antarctica. (AP Photo/Evan Vucci, Pool, File)
This article originally appeared on VICE US.