Dreams are really personal and one thing to one person can mean something totally different in someone else's dream. However, we do share many associations as we are all living on the same planet and in the same cultures and societies, and are biologically very similar to one another (same species) and deal with many of the same problems and experiences.

I imagine that most people would associate tornadoes with being a destructive force that we can't control, that is most probably what that represents. That doesn't really go very far in explaining the dream though, or finding the meaning. What specifically is the destructive force in your life which you can't control? Could it be a component of yourself? Some inner turmoil that you struggle to escape from? Only you can answer these questions.

It is very common for these 'fears' in dreams to be a component of yourself. Often the best thing we can do is confront our 'fears' in dreams, and try to embrace them with loving energy. It's important to try to accept them with loving energy because otherwise you are just feeding the fear by being afraid of it. Easier said than done I know! But once you are able to accept that part of your psyche and stop running away from it, you are able to see it for what it really is and make progress in dealing with the actual underlying issues which it represents. Only then will it stop recurring.

I think this is pretty much the essence of what dreams are and why they are so important. We need time for our subconscious to deal with this stuff and process information. Imagine how disorganised your house would become if you never took time to put things away and tidy up. It would just get worse and worse until it was not even functional any more. Same with the brain!

We experience dreams as weird stuff because the conscious mind has no way of interfacing with the subconscious in a way that the conscious mind can comprehend. That's why it is all so symbolic, it is just our conscious mind doing it's best job at interpreting what it is seeing in the subconscious.

Went off an a bit of a tangent here, sorry. Was fun to think about and try to articulate though :P I have a challenge for you, try to remember as much about one of these dreams as possible and try to write out at least some ideas of what you think it might mean. You might be surprised at how much you know and how much wisdom you come out with! It's all locked up there in your subconscious, you just got to let it out.