Continuity mistake: When the Wicked Witch tells Nikko "throw that basket in the river and drown him" The basket with Toto in it moves from one shot to the other in its position to the hourglass. (00:16:45)
Visible crew/equipment: Dorothy's bedroom window flies open in the tornado and the shadow of a crew member is moving on the wall on the right of the screen. (00:17:00)
Revealing mistake: Dorothy's bedroom window flies open and the wires pulling it can be seen glistening on the middle right of the screen. (00:17:00)
Visible crew/equipment: There's a second window on the left of Dorothy's bed and the shadow of the stage light can be seen on the wall behind it. (00:17:15)
Continuity mistake: Dorothy's house is outside of the tornado when we first see it up in the air. Then they are immediately inside the tornado. (00:17:15)
Revealing mistake: As the cyclone carries the farmhouse through the air, it is evident that the walls of Dorothy's bedroom are not solid walls, but fabric-covered flats. They flutter and vibrate in the wind. (00:17:50)
Continuity mistake: In the cyclone, Toto runs up to the window and barks at a cow. In the next shot Toto is gone. (00:18:00)
Continuity mistake: Inside the cyclone, looking out the window the wind is blowing left to right. In the room the wind is blowing in the window from the right. (00:18:05)
Continuity mistake: In the scene where the farmhouse is in the tornado, Dorothy is shown from behind with her pigtails in front of her shoulders. When the shot changes to the front, they are behind her shoulders. (00:18:05)
Revealing mistake: When the house lands in Oz, it lands with a bump and Dorothy is laying on her bed with Toto. The objects in the room had moved about a lot due to the twister, and wires attached to the end of the bed and the chair, etc. are really quite clear. (00:18:12)
Continuity mistake: The house we see in the cyclone has all of it's windows intact. When it lands they're all out. (00:18:40)
Revealing mistake: The glass in Dorothy's bedroom windows don't break, they are removed from their frames as the scene progresses, and if you look at the reflections in them the windows are made of plastic. (00:18:45)
Continuity mistake: When Dorothy first enters Munchkinland she steps out and in a front view we see her holding her hands close to herself, but when we look from behind, her hand is way out to the side. (00:18:50)
Continuity mistake: Dorothy's house just went threw a cyclone with chairs turned over, windows blown out and pictures knocked off the walls. Yet her comforter stays neatly folded and doesn't move from the bed. It's also changed and now has a plaid design on it. (00:19:05)
Plot hole: When the Gales' house lands in Munchkinland, Dorothy picks up Toto and glances around the house. She looks right out the window. Wouldn't she have noticed that she wasn't in Kansas then, before she got to the door? (00:19:05)
Visible crew/equipment: When Dorothy lands in Oz and exits the house to Munchkinland, the camera pans around the land. When it slowly pans over a large bed of tall flowers, you can clearly see a very large shadow passing over them. Obviously the shadow of camera equipment or a camera crane. (00:19:10)
Continuity mistake: During the tornado scene while she's in her bedroom, there is a small oval picture (which looks like Elvira Gulch) over the bed which ends up sideways. As she gets up to leave after the house lands, it's straight up. (00:19:15)
Continuity mistake: There are two actresses playing Dorothy (and two dogs playing Toto) as she opens the door to Oz. The first is a stand-in wearing a dull colored dress in order to make it look black and white. After she opens the door and moves out of the way, Judy Garland is who we actually see walking through. Look at the different pleats on the two dresses. (00:19:25)
Continuity mistake: Not only does Dorothy's hair change length during the film, it also changes shade. (00:19:40 - 00:22:15)
Continuity mistake: The bows in Dorothy's hair are tied differently throughout the scene with Glinda the witch in Munchkinland. (00:19:40 - 00:21:30)