This floodwater reached heights of perhaps 70 meters , with a volume of 110,000 cubic meters/second (m 3 /s), similar to that caused by flooding in the River Amazon. "Dating these floods has been fundamental to matching them to the advance and retreat of glaciers, and seeing how they relate to the climatic changes of recent millennia," says Alicia Medialdea, a researcher on the CENIEH Geochronology Program. Glacial recession The scientists identified a total of up to 86 catastrophic floods that took place in five phases coinciding with the end of neoglacial periods, when glacial retreat weakens the ice. Another period of major floods was about 6,000 years ago, with flows of up to 20,000 m