A giant iceberg has broken off Greenland's Petermann Glacier on the country's northwest coast and collided with a small rocky island, according to Wionews. The iceberg measured just over 76 square kilometres at the moment it separated from the glacier this summer.
Researchers tracked the ice mass using satellite imagery. It was spotted by chance by Adam Garbo, a glaciology PhD student at the University of Ottawa, while he was analysing data from the European Space Agency's Sentinel-1 satellite mission.
Scientists say it is the largest iceberg to break away from the Petermann Glacier since 2012, when a chunk of roughly 130 square kilometres separated from the same glacier. The Petermann Glacier is one of Greenland's largest glaciers and ends in a long floating ice tongue that extends into the sea.
An unexpected break
Researchers had actually been expecting a different outcome. They had spent a long time monitoring large cracks in the floating ice tongue of the Petermann Glacier and believed those cracks would eventually trigger a much bigger break. Their estimates suggested future icebergs of around 94 and 84 square kilometres could split off from that area.
Instead, the ice broke away from a different section of the glacier and turned out to be smaller than scientists had projected.
Collision with Joe Island
After breaking free, the iceberg began moving through the Petermann Fjord toward Nares Strait, the waterway that separates Greenland from Ellesmere Island in Canada. Over the course of a week, it travelled nearly three kilometres a day.
The iceberg then struck a small rocky outcrop known as Joe Island. NASA and the US Geological Survey's Landsat satellites captured the moment of impact, with images from 23 and 24 August showing the iceberg interacting with the island.
Such collisions usually have serious consequences for large ice islands, which often shatter after striking rock because of their shape and structure. This time, that did not happen.
Garbo said they had certainly watched closely how the iceberg interacted with Joe Island and were surprised it survived the encounter without breaking apart further.
What happens next
Scientists estimate the iceberg was less than 150 metres thick at the time it broke off. It is currently continuing to move southwest through Nares Strait.
The ice mass is expected to keep drifting for several more weeks before running aground. After that, it will likely begin breaking apart into smaller pieces.
As the iceberg melts, it will release a large volume of fresh water into the ocean. Its movement also poses a potential hazard to ships that may cross its path.
