Birth of an Iceberg

Birthing large icebergs is nothing new for the Pine Island Glacier. Among the fastest moving glaciers in Antarctica, Pine Island drains about 79 cubic kilometers (19 cubic miles) of ice per year from the West Antarctic Ice Sheet. The end of the glacier stretched about 48 kilometers (30 miles) past the edge of land, floating on the ocean. As more ice flows toward the water, the tongue grows longer. Eventually, a piece will break off, forming a large iceberg.

The last calving event occurred in late 2001 and resulted in an iceberg that measured 42 kilometers by 17 kilometers (26 by 11 miles). That event, too, was preceded by a large crack that was observed in satellite imagery in late 2000.

While satellites have tracked the formation of new icebergs, this is the first detailed airborne survey of such an event. “We are actually now witnessing how it happens,” 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.”

IceBridge scientists were surveying the Pine Island Glacier to learn how the glacier is changing and why. In the largest airborne survey of Earth’s polar ice, the airplanes of Operation IceBridge carry an array of instruments to measure the ice from top to bottom. The research team is gathering data about how thick the ice is (about 500 meters or 1,640 feet in the region of the crack); what the ground beneath it looks like; and how the glacier has changed over time. All of this information will help scientists understand why the Pine Island Glacier drains so much ice to the ocean and how much it could contribute to sea level rise in the future.