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A Very Bad Break

A massive, 160-square-mile block of ice broke off from the Wilkins Ice Shelf, in western Antarctica, last Tuesday. The shelf has been around for about 1,500 years. It covers about 5,000 square miles of the Antarctic peninsula.

Scientists track ice shelves carefully. When they noticed that the shelf was breaking, they were able to move satellites and an airplane into position in time to capture the collapse in photos and on video.

"It's an event we don't see very often," says Ted Scambos, a scientist at the University of Colorado. "The cracks fill with water, (then ice chunks) slice off and topple," he says.

Scientists fear that this collapse will cause the remainder of the Wilkins Ice Shelf, which is about the size of Connecticut, to break away.

There have been bigger collapses. In 2002, a chunk of ice more than 2,100 miles square about the size of Rhode Island shattered and separated from the Larsen B Ice Shelf, forming a 40-mile-wide iceberg. The sheet of ice had existed more than 10,000 years ago during the Ice Age. Scientists blame the increase in ice shelf collapses on rapid warming of the area in recent decades. Six shelves have collapsed in 30 years.

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