Breaking up is hard to do – or so they say. However, that is just what has happened to the Petermann glacier in north-west Greenland. In early August, ESA’s Envisat orbiter observed a huge slab of ice as it broke away from the lower end of the glacier, creating the largest iceberg in the northern hemisphere.
The Petermann glacier is one of the largest rivers of ice that flow toward the Arctic Ocean from the centre of Greenland. Some of these glaciers extend a floating ‘ice tongue’ into the sea. The tongue of the Petermann glacier was the largest in Greenland, reaching about 70 km in length. However, recent satellite images revealed that several cracks had appeared on the its surface, suggesting that a break-up was imminent.
An Envisat radar image taken on 3 August showed that the ice tongue was still intact. However, by the next day a huge chunk of its lower end had broken free. The result was a new iceberg that measures about 30 km by 14 km – larger than Paris or Brussels. It is now floating toward the open sea, where it could be a hazard to icebreakers sailing between Greenland and Ellesmere Island.
Small icebergs are often calved from the Petermann glacier in summer, but this year’s breakaway is unusually large. Envisat’s radar instrument will continue to monitor the movement of the frozen giant in the coming days and weeks. The radar imaging system is particularly suited to observe polar areas, as it can acquire images through cloud or fog, 24/7.
