In several scenes Max suffers from heart problems. In a later interview, Fred Gwynne said that he actually had a real heart attack while filming one of those scenes. The cameras kept rolling as they called 911, and the director decided to keep the footage of the real heart attack in the movie. Fred got out of the hospital a few days later, and managed to finish the filming on schedule.
In the scene where Lou Diamond Phillips is being dragged under the car, Philips actually did the stunt himself. He stated in an interview he had marks on his back for months after filming was complete.
In the scene where Ed O'Neill's character George Denver tries to cross the river, O'Neill actually submerged himself in the ice cold water without the aid of a stunt double.
Hoyt Axton liked the Montana filming locations so much, he bought property there after the film wrapped.
The pig dung in the back of the truck on which Fred Gwynne, Lou Diamond Phillips, and Rubén Blades hitched a ride to town was actually tons of chocolate pudding.
John Badham: As the TV news reporter. Badham was one of the executive producers on this film along with Rob Cohen, both of whom worked with writer and director Jim Kouf on Étroite surveillance (1987) the year before.