Massive sudden super freezing in the atmosphere in polar regions triggering world wide rains and floods elsewhere...massive earthquakes opening the underground rivers onto the world. The sudden super cooling froze many of the mammoths and other beasts in place and the flooding covered them rather quickly and the left over frozen glaciers kept them entombed under ground. It was a quick death for them at least.
Days of Noah!
Hmm... interesting hypothesis, I guess I never associated flash freezing with world wide flooding, but massive storms can certainly be driven by massive temperature differences, so I guess it’s something to think about.