Satellite images from NASA show that the Jakobshavn glacier, the fastest-moving in Greenland, shed 4.8 square miles of ice, resulting in one of the most dramatic calving events in history.
Radar images feature the glacier before and after the calving event which occurred between Aug. 14 and 16. Comparing images recorded last July 27 and those captured from Aug. 13 to 19, Jakobshavn is shown with its face inland at what is considered the furthest easterly location it has achieved since researchers started monitoring the glacier in the mid-1880s.
"The calving events of Jakobshavn are becoming more spectacular with time ... These images are a very good example of the changes taking place in Greenland," said Eric Rignot, a glaciologist from NASA's Jet Propulsion Laboratory.
The images suggest that before ice calving occurred, the glacier first moved westward from July 27 to Aug. 13. When the ice retreated after the calving, the Jakobshavn had lost 4.8 square miles of ice. If the ice is assumed to be around 4,600 feet deep, then the lost volume will be equivalent to 4.2 cubic miles, which could be enough to cover Manhattan with a layer of ice around 985 feet thick.
With the Jakobshavn draining 6.5 percent of Greenland's ice sheet, it is responsible for about 10 percent of the icebergs in the ice sheet, which amounts to some 38.6 tons of ice calved each year. Melting in the glacier could contribute to rising sea levels more than any other single feature within the Northern Hemisphere.
Events similar to the historic loss of ice have been documented on the glacier as well as it lost 2.7 square miles of ice once in 2010 and earlier in 2015.
The Jakobshavn has been studied for more than 250 years and its activities has greatly helped in understanding the importance of glaciers and ice streams in icecap glaciology, climate change and how sea levels are affected.
Icebergs are usually so big that it's impossible for them to easily float away, sometimes remaining stuck to a fjord's shallower area until they melt, which allows for breaking into pieces. If an iceberg doesn't melt enough, sometimes it breaks when hit by other icebergs coming from behind.
Radar imaging allows images to be captured in the dark or when clouds are present, making it highly useful for maritime surveillance, monitoring ice sheets, charting sea ice and improving ship safety.
