[Oh hey it's that girl from before. Rory sounds surprised through]

You've never seen snow before? [Okay, maybe that wasn't the right way to go about it] It's frozen water. I guess it's gotten cold enough for it...although a bit strange to be so sudden. Anyway, it's what happens when water gets really cold and falls from the sky. Used to play in it all the time as a kid. Once it piles up you should give it a try.