Continuity mistake: When Carol Ann is in the kitchen while her mom is doing the chair demonstration she is holding up a toy with her left hand and helmet in the right hand. When chair slides across the kitchen floor a close up shows Carol Ann yawning then immediately back to her holding the items. Clearly they inserted the yawn scene in as an after thought.
Continuity mistake: The window in Robbie and Carol Ann's room never has a mini blind. After the tree breaks through the window and the family races up to their room the window is intact with a blind in it. (00:39:00)
Continuity mistake: In the pool, Diane is surrounded by at least 4 bodies floating together; however, when she grabs the hose to climb up, half a second later, the overview of the pool shows just 2 bodies quite a distance each away from each other. In the next close-up, the 4 bodies reappear.