After Bill Paxton died, Spotter Network choreographed 200 storm chasers to spell out "BP" with their GPS tracker blips on a radar display to honor him. This kind of tribute had only been done five times before, and it was the first time it had been done for someone who wasn't a storm chaser.

Filming in Oklahoma was briefly delayed due to the bombing of the Alfred P. Murrah Federal Building in Oklahoma City on April 19, 1995. Many of the crew went to the site to help with recovery efforts.

A recording of a camel's moan was slowed down and used as the sound of the tornado.

The first movie released on DVD, and the last released on HD-DVD.

Both Joss Whedon and Steven Zaillian were brought in as script doctors at a fee of $100,000 a week.

According to urban legend, a tornado hit a drive-in theater in Stoney Creek, Ontario, while this movie was playing. In reality, a tornado hit a drive-in theater in Thorold, Ontario, on May 20, 1996, damaging a screen. The movie was not playing when the tornado hit, but it was scheduled to play that evening.

The real town of Wakita, Oklahoma had part of its old downtown area demolished by the film crew for the scenes after the twister passes. The studio then paid for the downtown to be rebuilt. The town also kept the new fire truck used in the film.

(at around 42 mins) According to the book on the making of the movie, the CGI cow picked up by the twister sisters was originally a CGI zebra from Jumanji (1995).

A jet engine from a Boeing 707 was used to generate wind in some scenes.

In a public Q&A at a screening of the film, Bill Paxton said he didn't meet executive producer Steven Spielberg until a year and a half after finishing the movie. He said Spielberg greeted him with, "Thanks for making me a lot of money."

(at around 1h 9 mins) The characters are alarmed when TV screens go blank, showing only static, before the tornado hits. In the days before digital TV, it was discovered that tornadoes generate a signal that will override and blank channel 2 on TV sets. Digital TVs do not react that way.

Having a very loud and bass heavy surround channel, this film was notorious for destroying many surround speakers all over the theatres in US and world wide.

Many of the news reports spread throughout the movie are actual weathermen from Oklahoma news stations, including Gary England, chief meteorologist at KWTV in Oklahoma City, and Rick Mitchell, chief meteorologist at KOCO in Oklahoma City. The "1969" footage of Gary England giving the televised tornado warning to Jo's family is actual archived footage of him issuing a tornado warning; however, Gary England did not join KWTV until 1972.

The project was a co-production between Universal and Warner Bros. That is why the drive-in marquee shows Psycho (1960) a Universal release and The Shining (1980), a Warner Bros. release.

Helen Hunt was injured while filming the scene where the truck drives through the corn, when the door was forced back into her head. For later shots, the door was wedged open.

Shot over a period of 95 days.

The instrument package used in the movie, "Dorothy", is an homage to the instrument pack real tornado researchers attempt to place in the paths of tornadoes, "T.O.T.O.".

In an early scene when Philip Seymour Hoffman is sitting on a lawn chair, he lifts his leg in the air while laughing. His genitals were fully visible for a split second. It was edited out of the DVD and VHS releases, but it was leaked from VHS screeners sent to industry professionals.

Michael Crichton and his wife Anne-Marie Martin were paid $2 million for their script.

In order to get the background skies looking suitably stormy, the truck cab sequences had to be flooded with high-intensity lighting for contrast. As a result, Helen Hunt and Bill Paxton suffered minor retinal burns through much of the filming.

(at around 53 mins) After the team leaves Wakita, there is a seemingly impossible helicopter shot in which the camera descends several hundred feet in a matter of seconds, ending up mere feet from the convoy. This was achieved by having the cars drive slower than usual and then speeding up the film.

(at around 58 mins) Jan de Bont said he regretted thinking of the hail sequence because it took so long to do and was very difficult. Also the crew couldn't find ice blocks big enough in Oklahoma for the hail making machine. They ended up having to find them in other states and some were obtained from the Burlington Ice Company in Burlington, Iowa. The ice blocks were made special by pouring milk in with the water, so the hail would show up better on film.

Tom Hanks was the original choice for the role of Bill Harding. Hanks read lines with the cast and even chose the character's wardrobe, which stayed in the final film, before dropping out. Kurt Russell and [Michael Keaton] were other possible considerations. Bill Paxton was chosen due to his "southern every man charm" on a recommendation from director James Cameron.

In the town of Wakita, the building the actors used to get ready for filming was turned into a museum for the movie where they have "Dorothy" on display as well as many other items from the movie.

Trailers contain a shot not in the film: a truck tire hurtling towards the viewer. This was supposedly one of the test shots that was created during pre-production to prove that CGI was capable of executing the effects sequences with the necessary level of realism.

Helen Hunt previously auditioned for the role of Dr. Ellie Sattler in Jurassic Park (1993).

"It sucks" was originally going to be used as one of the taglines for the film, but the producers felt that it worked too much to the advantage of disappointed audiences and critics.

The base camp (where the crew trucks and equipment are staged) for the end sequence was at a pig farm down the road from the well-house. Every morning the cast and crew were greeted by the smell of a 2-acre pig-waste holding pond in the middle of all the trucks.

The unique siren sound made by Dorothy is achieved by combining the sounds created by a standard police, fire, ambulance siren control head. These control heads have modes called yelp, siren, and phaser. This same sound would later be heard during the chase scene from Terminator 3: Rise of the Machines (2003), with the fire truck, crane, ambulance, police cars, all chasing the Toyota Tundra. In the latter movie the sound was created accidentally. In this movie on purpose.

(at around 1h 30 mins) The name on the tanker truck that pushes Bill's pickup off of the tree is "Benthic Petroleum" which is the same oil company that Ed Harris' crew works for in The Abyss (1989). Ed Harris majored in theater at the University of Oklahoma where the National Severe Storms Laboratory is located.

The kinetic wind-powered sculptures in aunt Meg's garden are made by sculptor Evan Lewis.

Jonas is vilified for selling out to 'corporate sponsors', which is ironic considering Pepsi's very prominent product placement. When the team is making the 'wings' for the sensors, all of the cans are Pepsi products. In almost all the shots showing the 'Doppler', the colors spiral inward and morph into the Pepsi symbol.

The laptops used in the film are Silicon Graphics Indy Presenter LCD screens (not real laptops) that have been modified to look like functional laptops when in fact the screen image is generated by a computer off-screen.

One of the Dorothys used during filming is now located 650 feet underground in the Underground Salt Museum in Hutchinson KS. They also have the original film reel.

(at around 1h 14 mins) Lois Smith's character is reading Dante Alighieri's Inferno when the twister hits Wakita. The book also features a tornado in the second circle of Hell that punishes people ruled by Lust.

Although Amblin Entertainment has collaborated with both Warner Bros. and Universal on many occasions (Amblin co-founder Steven Spielberg directed films for both studios), as of 2014, this film marks the only time Amblin collaborated with both studios on the same film.

Winds on the plains in Oklahoma change and gust regularly, and wind speeds are typically higher than much of the rest of the country. Several characters are shown deeply contemplative about or reacting to a relatively gentle wind picking up outside (e.g., Aunt Meg before the Wakita tornado). While this makes for suspenseful storytelling, people in this region would be much more likely to notice the wind stopping as a sign that a storm is fast approaching.

(at around 1h 35 mins) Right after Bill and Jo come out of the toppled house, the teddy bear that hits their truck is CG.

Laura Dern and Tom Hanks were considered for the roles of Dr. Jo and Bill Harding.

The instrumental rock song in the ending credits is "Respect the Wind", written and performed by Eddie and Alex Van Halen.

The reason Dustin is wearing the OU (University of Oklahoma) hat is because the producers wanted to spite OU for not letting the OU symbol be on Dorothy.

(at around 59 mins) As one of the characters looks at the screen of their weather computer, he screams "That's no moon, it's a space station!" This is a reference to Obi-Wan Kenobi's line when he, Luke, Han, and Chewbacca first discover the Death Star in Star Wars: Episode IV - A New Hope (1977).

Jan de Bont, a vegetarian, has stated that he hated filming the scene at Aunt Meg's house when everyone is eating steak and eggs.

It was Steven Spielberg's idea to kill off the father in the opening scene. Originally he would have survived but it was decided his death would establish how dangerous tornadoes can be and the reason for Jo's obsession with them later in life.

Garth Brooks turned down the role of Dustin Davis.

One of the reasons Jan de Bont signed on to direct the film was that, given the rapid rise of CGI in the 1990s, he saw this as perhaps the last opportunity to direct a large-scale film with practical effects.

The red combine used in the film is now in Watrous, Saskatchewan, Canada

Jan de Bont is a fan of singer Tori Amos, and decided early on he wanted to include some of her music in the film.

Jami Gertz's first acting role was a school production of The Wizard of Oz, in which she played Dorothy.

The 21 August 1995 draft of the screenplay credits Joss Whedon and Jeff Nathanson as writers. Neither are credited in the final film.

Two of the character's names are Stanley and Kubrick.

Cary Elwes role as written was cut back significantly in the editing room.

The explosion of the oil tanker was originally mistimed and was not caught on film. De Bont decided not to tell the studio immediately and the stunt was reset and filmed again, costing a rumoured $500,000.

The name "Dorothy" and the picture on the side of the device are an homage to Judy Garland in her role of Dorothy Gale in The Wizard of Oz (1939)

The drive-in theater screen is showing The Shining (1980) starring Jack Nicholson, who would star opposite Helen Hunt (Jo) in As Good As It Gets (1997), released in the year following this film.

In her introductory scene Helen Hunt clearly says the f word but you don't hear it. This was edited out for home video, presumably to secure a more family friendly rating.

Tom Hanks, Kevin Costner, Richard Gere, John Travolta, Mel Gibson and Dennis Quaid were considered for the role of Bill Harding.

(at around 25 mins) When Jo and Billy's team are chasing a tornado in the cars, they play some songs: Dusty plays "Child in Time" of Deep Purple in a TV; Preacher hears "William Tell Overture" on the radio car; and Beltzer and Haynes sing "Oklahoma".

Six of the top 10 billed actors either starred or co-starred in 1 or more 80s cult classics: Helen Hunt - Girls Just Want To Have Fun, Project X, Peggy Sue Got Married, Next Of Kin Bill Paxton - Aliens, Science, Stripes, The Terminator, Next of Kin (played Helen Hunt's brother-in-law) Cary Elwes - The Princess Bride, Glory Jami Gertz - The Lost Boys, Less Than Zero, Sixteen Candles, Crossroads Alan Ruck - Ferris Bueller's Day Off, Bad Boys Todd Field - Gross Anatomy

The first music video played by Dusty in the TV of his van is Eric Clapton "Motherless Child". Later, he played Deep Purple "Child in Time".

Early on chasing after Jo(Helen Hunt) Jonas(Cary Elews) pulls up alongside Bill(Bill Paxton) and Bill calls him a "Nightcrawler". Bill Paxton would go to co-star with Jake Gylenhall in the film Nightcrawler, though in this film the remark refers to Jonas being not as competent a storm chaser as Bill and Jo whereas in Nightcrawler it refers to independent or stringer camerapersons capturing violent and bloody footage for news stations.

Both Jeremy Davies and Sean Whalen would later appear in the TV show Lost (2004).

The roadside cafe featured early in the film is called the "Blue Tulip", which is the name of Jan de Bont's production company.

Christopher McDonald was considered for the role of Dr. Jonas Miller, but was already committed to Happy Gilmore (1996) where he coincidentally plays a similar arrogant, smug villain.

In the Spanish dub, Billy's nickname "The Extreme" was translated as "El Máximo" (The Maximum).

Bill Paxton and Helen Hunt previously appeared together in Next of Kin

Early in the film during a storm chase, the chasers quote dialog from Repo Man (1984) to each other over the radio.

(at around 1h 40 mins) At the end of the movie Bill remarks that the tornado didn't take the house. In fact, it was originally supposed to. The Hardin County, Iowa, Historical Society and many citizens objected to the house being blown up so it was spared. The area is now a tourist attraction as the rubble from the barn and fences is still there exactly as it was in the movie.

Despite the severity and frequency of the tornadoes in this movie, there are only 3 known deaths: Jo's father, Jonas, and Eddie.

(at around 1h 14 mins) In the scene right before aunt Meg's house gets hit by the tornado you can see a movie playing on her TV and the actress you see is Judy Garland, who plays Dorothy in the The Wizard of Oz (1939).

There are a total of eight tornadoes in the film.

The set-piece where the F5 tornado begins hurling farm machinery into Jo and Bill's path was achieved by suspending the equipment from powerful helicopters and then releasing them on cue. The red pickup was then driven through the wreckage as it hit the ground and CGI was used to add debris including the steel wheel that bounces in front of the camera. The collision of the truck's window with one of the parts of the harvester is real and was not intended, hence the continuity error where it appears intact in the following shots.

(at around 50 mins) During Aunt Meg's house lunch, Melissa asks about if exists a tornado F5, and if someone of the team have seen one. Ironically, she leaves Billy after the tornado happened in the drive-in theater, just before of the final tornado of the movie. This final tornado was an F5.