Scientists from the University of Copenhagen, Denmark, have for the first time observed a rare natural phenomenon - glacial flooding in Greenland. More than 3 trillion litres of meltwater poured out of a lake in the eastern part of the island over several weeks. The study highlighted the "enormous and potentially dangerous forces" that meltwater can unleash. Catalina Lake in East Greenland holds three times the annual water consumption of the whole of Denmark. It dumped 3.4 cubic kilometres of meltwater into the Scoresby Sound fjord.