This is a video that was posted on youtube on Tuesday.  It says this took place in "South Dakota" other information says it took place in Watford City, ND which is north of Dickinson, ND.

As a tornado approached these guys they video taped the whole thing.  When asked about this video Sioux Falls National Weather Service Meteorologist Todd Heitkamp stated:

"It is very ill advised for any untrained person to video tape a tornado".

The video opens with the guy exclaiming: "Oh My Gosh!"  As these guys realize that they have no where to go.  From there the language gets stronger and the video gets much more dramatic.  It's unbelievable footage.  *WARNING STRONG LANGUAGE*