Other mistake: When the blue van rolls over, and they turn around to go pick them up, they park like 20-30 feet from the van for no reason, instead of right by it, seemingly just to have a tree block their path, then decide to run into a church with really big stained glass window and wood pews while a fire tornado is just outside. Rolling the van back upright, all the TVs and equipment inside the van seem to be working just fine.
Factual error: What kind of small American town has an airport that has 6 jumbo jets sitting on the runway? I mean, I think Dallas is the closest airport in the region that would have 4 engine 747s at the ready. Topeka, Oklahoma city, etc. commercial airports could barely handle one 747, let alone 5-6.
Continuity mistake: In the scene where they're leaving the school, there are a ton of cars behind them on the highway and then all the cars just disappear.
Suggested correction: Our heroes are in the last bus. There are a few cars exiting behind them, but you see at least one of the cars pass the bus and get ahead of it. In the first aerial shot of the highway, you can only see two cars behind the last bus. When the tower falls, it lands just behind the second-last bus, cutting off 3 cars, then our heroes' bus, then the Titus and another 2 cars. At no time is there a line of cars behind the last bus that disappears.
Revealing mistake: When Alison is holding on to the Titus, Gary tries to save her, and they are seen dangling in the air by the tornado. In the shot of Trey looking out the bank window, you can faintly see wires attached to Alison to make her dangle in the air.
Continuity mistake: In the scene near the end when they are taking cover in the storm drain, the manhole cover is stripped away by a combination of the wind and a flying semi truck. As the tornado reaches its strongest winds, the manhole cover, which is mysteriously back somehow, flies off again, this time by wind alone.
Other mistake: They had two cameramen, one meteorologist, and one driver who ran the imax camera. One camera man dies before they get in the church then when they talk about why he died you see another camera man or crew member holding a camera. He's seen twice then never seen again.
Suggested correction: Lucas, the 3rd cameraman, is in the background throughout (or we're seeing through his camera). He goes with Allison and the others after the church (Pete: "Suit yourself"); he gets out when they reach the industrial park, but is filming instead of helping rescue Donnie and Kaitlyn; he's behind Pete when they're all crammed in the Titus; he gets back in the Titus with Pete at the school (Pete: "Lucas, you getting this?"); and he's there in the storm drain and when they come out at the end.
Continuity mistake: When the blue van is blown over, Titus turns around and the road is wet with puddles but as he drives on the grass/dirt it's dry. (00:51:29)
Continuity mistake: After Donk has successfully jumped into the flaming pool on an ATV, he takes off the goggles he was wearing and puts them onto his helmet. He hugs his friend, Reevis, and after a cut the goggles are back over his eyes, only to be put back up once again.
Continuity mistake: School security cameras have 3 separate time stamps. 18:19 then 13:53 then 20:07.
Other mistake: Public schools also have dress codes for faculty/staff, and female employees should not wear anything too "revealing", such as showing cleavage. Trey showed Donnie a photo he took of a teacher, saying that he got "a nice shot of Miss Bell's cleavage." A teacher would not be likely to wear what she had on - the "cleavage" would be considered, at minimum, "disruptive" to the learning environment (especially to high school boys). (00:14:54)
Other mistake: Public schools have dress codes, though they have become more liberal (lax). One thing that continues to be prohibited is the rule against wearing "revealing" clothing. Kaitlyn is wearing a blazer over her quite "revealing" low V-necked top, but the design of the blazer doesn't make it very useful for her to "cover up" and be in compliance; she would likely be sent to the office (not class) until she finds something more appropriate, which may entail having her parent bring a suitable top. (00:16:03)