Mamouth Piece of Ice Breaks from Glacier

A block of ice mesuring 100 square miles has separated from the Petermann Glacier, on the north-west coast of Greenland.

It is the largest Arctic iceberg to calve since 1962, said Prof Andreas Muenchow of the University of Delaware.

The ice could become frozen in place over winter or escape into the waters between Greenland and Canada.

If the iceberg moves south, it could interfere with shipping, Prof Muenchow said.

Cracks in the Petermann Glacier had been observed last year and it was expected that an iceberg would calve from it soon.

The glacier is 620 miles south of the North Pole.  

There was enough fresh water locked up in the ice island to "keep all US public tap water flowing for 120 days," said Prof Muenchow.

He said it was not clear if the event was due to global warming.