Aug 13, 2010 08:02 GMT  ·  By
The ASTER instrument on NASA's Terra spacecraft captured this image of a massive iceberg from Greenland's Petermann Glacier on August 12, 2010
   The ASTER instrument on NASA's Terra spacecraft captured this image of a massive iceberg from Greenland's Petermann Glacier on August 12, 2010

NASA is keeping an eye on a massive iceberg, that broke off a glacier in Greenland about a week ago.

Officials at the American space agency say that the large chunk of ice, which is about four times larger than Manhattan, could reach a position from which it could threaten shipping lanes in the region.

This will happen especially if the ice mass becomes trapped in the Nares Strait, the swath of ocean surface separating Greenland from Canada.

If this happens, then the flow of ice from the Arctic Sea to the Atlantic Ocean could be interrupted, which means that ice will accumulate in a very narrow region, blocking anything that wants to pass through.

The area most at risk is Baffin Bay, the sea connecting the Arctic and Atlantis. Experts say that ice bridges may form here, if the massive iceberg does not pass through Nares.

The massive iceberg separated from the Pettermann Glacier in Greenland, one of the two remaining glaciers still featuring a tongue extending into a floating ice sheet.

“The Petermann Glacier lost about one-quarter of its 70-kilometer-long (40-miles) floating ice shelf, according to researchers at the University of Delaware, Newark, Dela,” say experts at the NASA Jet Propulsion Laboratory (JPL), in Pasadena, California.

“The recently calved iceberg is the largest to form in the Arctic in 50 years,” they add, saying that ice island broke off its parent ice sheet on August 5.

The iceberg has a surface of about 251 square kilometers (97 square miles), and experts estimate that the amount of freshwater it contains could fuel the entire Hudson river for a full two years.

The Petermann Glacier is the largest free-floating one in the Northern Hemisphere, so experts say that it calving off large ice islands is nothing new.

But that doesn't prevent NASA from keeping an eye on the situation, by using its Terra satellite.

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument snapped a new image of the large chunk of ice yesterday, on August 12.

The photo covers a swath of land 49.5 by 31.5 kilometers (30.7 by 19.5 miles), which is located at 81.1 degrees north latitude by 61.7 degrees west longitude. Follow me on Twitter @TudorVieru