This is a Really Weird Dream that I Had....?

So, my hometown (although in the dream it looks nothing like my hometown at all) totally floods, water over rooftops and everything! The water is super clear though, like pool water. I go snorkeling (although I'm completely submerged and can breath underwater in dreams anyway) and I'm wearing a frilly, red and white, floral, one piece bathing suit. So I go snorkeling and as I turn a corner, there is this HUGE great white shark there. His face is almost as big as a house (I didn't see how long he was). He just roars (sharks can't roar, I know) and shakes his head as I remain petrified by fear. Then, I woke up. I had this dream when I was six, and many years later, our school DOES flood!!! Weird, right! Can someone please interpret?