If the Petermann glacier breaks up back to the upstream rift, the loss would be as much as and additional 160 sq. km (60 sq. mi); a loss of one third of the massive Petermann ice tongue. The Petermann glacier thins from 600 m thickness at the grounding line to 70 m at the terminus. The crack is advancing to a point where a massive breakup seems imminent, in which case, the area of break-up would be 56-60 sq. miles (147-160 sq. km). Credit: Byrd Polar Research Center, Ohio State University