blondie:
The Jews did not live in Egypt their whole existence. Jacob and his family moved down there when Joseph was second in command.
Also from the age of 40 to 80 Moses lived with his wife's family near Mount Horeb (Sinai) where it snows.
There's no evidence that Moses existed or that the Jews were slaves in Egypt. The 'Exodus' story is a re-write of older Ethiopian stories and other myths. Like the other books attributed to Moses, 'Exodus' was written in the 6th century BCE. It's self-evident that the authors were familiar with snow, and not remarkable given that people would have at least seen snow-peaked mountains from a distance, and heard about snow through traders, even if they had not themselves experienced snowfalls.