Because overcast skies were not always available, De Bont had to shoot many of the film's tornado-chasing scenes in bright sunlight, requiring Industrial Light & Magic to more than double its original plan for 150 "digital sky-replacement" shots. Principal photography was originally given a deadline to allow Hunt to return to film the fourth season of her NBC sitcom "Mad About You", but when shooting ran over schedule, series creator and actor Paul Reiser agreed to delay the show's production for two-and-a-half weeks so "Twister" could finish filming. De Bont insisted on using multiple cameras, which led to the exposure of of film, compared to the usual maximum of .