The filmmakers from Twister slowed down what animal’s sound to create the noise of the tornado?

The answer is: Camel’s Moan. A recording of a camel’s moan was slowed down and used to create the ominous sound of the tornado. A jet engine from a Boeing 707 was used to create wind for some scenes. The film had a notoriously loud and bass-heavy surround channel and destroyed speakers in theaters worldwide upon release.Source