A massive ice island four times the size of Manhattan has broken off an iceberg in north-western Greenland, a researcher at a US university said. Andreas Muenchow at the University of Delaware said in a statement Friday that the last time the Arctic lost such a large chunk of ice was in 1962. Muenchow's research focuses on the Nares Strait, a region between far north-eastern Canada and northwestern Greenland, about 1,000 kilometers (620 miles) south of the North Pole. Early on Thursday, "an ice island four times the size of Manhattan was born in northern Greenland," said Muenchow. The freshwater stored in the ice island could "keep all US public tap water flowing for 120 days," Muenchow said. Satellite images of the area show that the Petermann Glacier lost about one-quarter of its 70 kilometre long floating ice-shelf. The Petermann glacier is one of Greenland's two largest glaciers that end in floating shelves, and connects Greenland's ice sheet directly with the ocean. Muenchow credits Trudy Wohlleben of the Canadian Ice Service with detecting the ice island early Thursday, hours after raw data from a NASA satellite was downloaded, processed, and analyzed at the university. The ice island will enter Nares Strait, between northern Greenland and Canada, where it will run into small islands. "The newly born ice-island may become land-fast, block the channel, or it may break into smaller pieces as it is propelled south by the prevailing ocean currents," said Muenchow. The ice island could then head along the Canadian coast and reach the Atlantic within the next two years, he said.