When the Tinman was doing his dancing and then toots his funnel hat after he met Dorothy and the Scarecrow, watch Toto the dog near him. When Tinman tooted his funnel hat, Toto was startled.

At the beginning of the movie, where the twister was going through a field towards Dorothy's house, you can see the twister getting closer. Then in the next shot, the twister was farther away, and then later it gets closer to the house again.