I was citing Biblical history. You’ve read the book, or no?
Assuming a biblical timeline, massive amounts of volcanic activity took place during the Flood year and immediately afterward. The volcanic ash from these eruptions would have blocked out enough solar radiation to cool the atmosphere for hundreds of years after the Flood waters subsided—just what was needed to form the thick ice sheets that existed during the centuries-long ice age.
I've read the book, must have missed the part about all the ice that lasted for "Centuries" after the flood. I would have thought that someone may have mentioned it since Noah and his band of survivors probably didn't plan on winter gear when they landed.