Jakobshavn Isbræ, also known as the Jakobshavn Glacier and Sermeq Kujalleq is a large outlet glacier in West Greenland.
It is one of the fastest moving glaciers, flowing at its terminus at speeds of around 20 metres per day. It produces around 10% of all Greenland icebergs. Some 35 billion tonnes of icebergs calve off and pass out of the fjord every year. Icebergs breaking from the glacier are often so large (up to a kilometer in height) that they are too tall to float down the fjord and lie stuck on the bottom of its shallower areas, sometimes for years, until they are broken up by the force of the glacier and icebergs further up the fjord. Studied for over 250 years, Jakobshavn Isbræ has helped develop our understanding of climate change and icecap glaciology.