Why do I often dream about tornadoes?

I slept for four hours this afternoon because I didn't get much sleep last night. Anyway, I dreamed about being chased by a tornado. I have these dreams once in a blue moon. I remember back in '95 when I was 16 I had a dream about a giant black tornado. I was in an airplane, and it was chasing me. As I looked out the window the tornado had flaming red eyes, and it glared at me. I had another dream about a giant white tornado with glowing green eyes. It chased me as I rode on top of a box car of a speeding train. Today I dreamed about a gray tornado with purple eyes trying to suck me out of the water as I dove into the river for refuge. What is up with these dreams about tornadoes?