Arctic Iceberg Splits in Two Near Greenland

(Sept. 11) -- The largest Arctic iceberg in nearly half a century has split into two pieces after crashing into a rocky island west of Greenland.

The iceberg – actually a massive floating ice island four times the size of Manhattan – broke off Greenland's Petermann Glacier last month. It was the largest such iceberg since 1962, with a surface area of 100 square miles and a thickness of about half the height of the Empire State Building.

After it broke off from Greenland, the ice island started floating slowly down the Nares Strait, a narrow waterway between Greenland and Canada. At the time, scientists thought it might get stuck in the strait, possibly blocking key shipping routes.
But satellite images show that it broke into two pieces after repeatedly smashing into Joe Island, a small rocky outcrop in the Nares Strait.

"In the satellite imagery, you can hardly see the island because it's so much smaller than the ice island, but it's there; it's a piece of rock," Andreas Muenchow, an associate professor at the University of Delaware who's been doing research in the Nares Strait, told CNN. "The forces of the ocean currents and the winds wiggling it on and off the island were too much."

Center for Ocean and Ice, DMI

A satellite image shows the ice island has split in two while passing through the Nares Strait.

The biggest ice chunk stretches over an area of nearly 60 square miles, or around 2.5 times the size of Manhattan, while the smaller piece is around 32 square miles. They're still floating down the Nares Strait toward the Canadian province of Newfoundland, but aren't predicted to hit land for another couple of years – by which time they'll likely melt substantially in size.

Greenland has been slowly losing mass for decades, as icebergs calve off it in a melting process scientists attribute to global warming. The U.S. Coast Guard's International Ice Patrol estimates that anywhere from 10,000 to 40,000 icebergs break off from Greenland's west coast in any given year.

But the so-called Manhattan iceberg was unusual because of its large size, which is more typical of Antarctica rather than the Arctic. The last time such a massive iceberg formed in the Arctic was in 1962, when the Ward Hunt Ice Shelf gave birth to a 230-square-mile ice island which also broke up in the Nares Strait.

Icebergs often break off from glaciers in the summer, when the ice begins to melt and gets thinner in some areas, triggering cracks. The process has been exacerbated by global warming, and the melting of arctic glaciers could lead to a rise in global sea levels.