Houses had thatched roofs-thick straw-piled high, with no wood underneath. It was the only place for animals to get warm, so all the cats and other small animals (mice, bugs) lived in the roof. When it rained, it became slippery, and sometimes the animals would slip and fall off the roof…
Hence the saying, “It’s raining cats and dogs.”
Respectfully Submitted by
Orlan Smith