WARNING: Some viewers may find images disturbing.  

HARRISBURG, Or. (CNN)-- Terrifying moments are caught on camera as an out-of-control monster truck crashes into the stands at a show.

It happened Saturday at the "Monster Air 2012" show in Harrisburg, near Eugene, in Oregon.

Onlooker Dustin Earls was recording video of a drag race when he captured the frightening scene. The truck driver lost control, bounced through a mud pit and over a barricade before smashing into spectators.

Three people were hit by the truck's 48-inch tires and taken to a hospital. A sheriff's deputy says their injuries are not considered life-threatening. The truck driver was not hurt.