This is part of the events of the end of the Pleistocene age. Which was the end of a long ice age. Geological evidence from around the world points toward there having been a lot of tsunami type tidal waves, that rolled over many parts of the world. Not all of the world, but a bunch. It also marked the end of the Neanderthal, and the Cro-Magnon species, that weren't seen later than that. Major extinction of species occurred at this same era of time. There is also found in those layers of geological deposits, a bunch of ash, unknown red mineral deposits, meteor/meteorite type material, and lots of animals and plants torn from the earth and wadded up by those large flows of water where they didn't belong. Along with large areas completely buried under sand and debris. Locations of events are scattered all over, but Northern China/Asia, and Alaska are well known in archeology and geology. Both adjacent to the Pacific. No one knows, but a best guess is that the Earth had a hit from an asteroid or comet, or a close pass through the atmosphere without actually hitting, from an extremely large one. The result was smoke, ash, geological movement (earthquakes), walls of water (floods), and an extended period of rain world wide. I'm sure there were rather extensive temperature fluctuations also, but have not ever seen data about that. The overall effect was that the temperatures went up quickly. Another best guess is that events were extreme at the beginning, settled into 40 days and nights of trauma, and lasted for over a year. The ice of that ice age was nearly completely destroyed. edit: There is an extremely large impact crater under the ocean North of Australia that might explain it all, but no one knows yet how old it is.