NASA scientists capture unprecedented measurements of iceberg in the making - CNN

(CNN) -- NASA scientists say they have captured the first-ever detailed airborne measurements of a major iceberg about to break off into the sea.

"A lot of times when you're in science, you don't get a chance to catch the big stories as they happen because you're not there at the right place at the right time. But this time we were," John Sonntag, a scientist with the NASA survey team that captured the data said in a video posted to NASA's website.

The discovery of the approximately 340-square-mile iceberg-to-be came October 14 as scientists were flying over the glacier as part of Project IceBridge, a six-year mission to map a three-dimensional view of Arctic and Antarctic ice, according to NASA.

Scientists aboard the flight noticed a large crack in the glacier and asked colleagues in the United States to review satellite data to see when it appeared, according to the NASA video. Those scientists said the 18-mile-long crack, which is now between 260 feet and 820 feet wide and up to 195 feet deep, appeared in early October.

The crack is the first step in the iceberg breaking off from the Pine Island Glacier and slipping into the ocean. Such events are fairly common but still major from a scientific perspective, Sonntag said.

The NASA crew was able to use laser range-finding tools to create a three-dimensional map of the rift, the first time such an image has been created, said IceBridge project scientist Michael Studinger.

"It's part of a natural process but it's pretty exciting to be here and actually observe it while it happens," he said in an article posted to the NASA website.

NASA did not indicate when the iceberg might break off from the glacier. When it does, the leading edge of the Pine Island ice shelf will have receded more than at any time since the 1940s, when the ice shelf was first mapped, NASA said.