Visible crew/equipment: When they are trapped in the garage and the tornado is whipping through, if you look real close when the debris is falling on them you can see (very quickly) a crew member throwing trash in the background.
Revealing mistake: They wouldn't be able to walk or run nearly so easily when near a tornado. In ametuer video footage of real tornados, the people could only move quite slowly, and were walking on an angle of 30 degrees from upright.
Continuity mistake: After leaving Aunt Meg's the first time, Jo and Bill are in the red truck. Bill says, "Ok, let's get you wired." When Jo looks over at him you can see that she already has the headphones around her neck. Then they cut to Bill and when he goes to put the headphones on her neck is bare. (00:53:20)
Continuity mistake: When we see the dog Mose in the movie he looks very young (2-3 years old). But in the scene when Bill and Joe's storm chasers crew watches Jonas's van gets picked up by the F5 tornado, the dog Mose has aged 5-6 years (when dogs age the fur around the face turns white).
Visible crew/equipment: There's a shot late in the movie at Helen Hunt's Aunt's house - the camera shows all of her home made "wind chimes" blowing in the wind. As the camera pans in and shows a little man sawing or axing something, you see a human hand appear near the bottom of the screen as the camera leaves the scene.
Continuity mistake: During the first tornado, Beltzer says the twister is about three miles away. You later see Bill turn the truck off the road directly onto that dirt path, not ten yards away. The tornado then arrives and sucks Jo's truck into the air. After the tornado, Melissa is driving along and says, "Oh my God" as the tornado disappears, back to about three miles away.
Factual error: Paxton and Hunt drive their truck toward the twister in a corn field, they jump out of the truck and then start running for it. Have you ever run in a corn field? You can't run in a corn field that has stalks that high, they would cut you to shreds. They would have been bleeding on the faces and hands and arms if they were wearing short sleeve shirts. If you enter a corn field, you must move with the rows - you cannot cross rows because the stalks are just like small trees and they are maybe six inches apart. (01:39:10)
Continuity mistake: When Jo's truck is lifted by the first tornado they encounter, it is dropped on the road in front of the red dodge driven by Bill's fiancée. When we see the truck drop, the drivers window is closed. As the dodge swerves to avoid hitting the other truck, the window is now opened. And finally, in the last shot where everyone is running to her aide, the window is closed again. (00:34:05)
Continuity mistake: Towards the beginning of the movie when Melissa goes on the chase after they leave Meg's, she is under an umbrella with her hair dry. They cut away go back, she is drenched, cut away go back she is soaked, go back again, she is wet. (01:00:05)
Continuity mistake: In the garage scene, an air hose comes on and Preacher grabs it. When he is hit by a hub cap and lets go of the hose, the air switches off.
Factual error: In the last scenes when Bill and Jo are in the shed with the water pipes, the shed is torn apart by wind as well as flying debris at hundreds of miles per hour. I have watched the scene numerous times and there is not so much as a scratch on their faces. Even if they lived, they would have been battered and bloody from debris. Regardless if tornadoes do weird things, the debris ripped the shed apart, which is stronger than a human body.
Visible crew/equipment: When Bill Paxton and Helen Hunt are driving up to Aunt Meg's house after the tornado has hit, you see a shot of the ruined home as they drive up. If you look carefully, you can see wires hanging coming out from the top of the house to keep it from collapsing until the filmmakers were ready.