A giant mass of ice, about the size of Virginia Beach, broke off of Antarctica’s Pine Island glacier last week and is slowly drifting away.

A crack at the glacier was first noted by scientists in October, 2011. Here’s NASA’s stunning view of the glacier after that initial crack:

Since that time, the crack expanded to the southwestern edge of the ice shelf before fracturing or “calving” in July. Last week, the massive iceberg finally “cracked off” the glacier and open ocean now separates the iceberg and the glacier’s “calving front” according to NASA.

NASA’s Operational Land Imager on the Landsat 8 satellite captured this before and after sequence of the iceberg on October 28 and November 13.

The iceberg is estimated to be 21 miles by 12 miles, or 252 square miles – roughly the size of Virginia Beach (249 square miles) or Singapore (275 square miles).

Now that the iceberg has broken off, researchers are keenly interested in where it’s headed.

“It is hard to predict with certainty where and when these things will drift,” says NASA glaciologist Kelly Brunt. “Icebergs move pretty slowly, and watching this iceberg will be a waiting game.”

Robert Marsh, a scientist at the University of Southampton in the United Kingdom tracking the ice, says it could eventually intersect Southern Ocean shipping lanes.

“There’s a lot of activity to and from the Antarctic Peninsula, and ships could potentially cross paths with this large iceberg, although it would be an unusual coincidence,” says Marsh.

NASA’s Brunt says it may be a long while until the iceberg exits Pine Island Glacier Bay.

“It takes a bit of energy and time to move these guys into the Southern Ocean,” Brunt added. “Many icebergs in Pine Island Bay have persisted for years before exiting, so this could be a long waiting game.”

NASA says this sort of “calving event” happens every five or six years. Hence it is “not necessarily a surprise” according to Tom Wagner, NASA’s cryosphere program manager.

Scientists are studying whether the frequency and nature of these events may change in the future due to global warming.

Update: NASA shares with us a current view of the now “ice island” in Pine Island Glacier Bay here: