GRANITE FALLS — Dash cam video released Thursday by the Yellow Medicine County Sheriff's Office shows a runaway school bus rolling down U.S. Highway 212 west of Granite Falls Wednesday afternoon and the moment a local firefighter dashes to the side of the bus to bring it to a stop.

Bill Flaten, Yellow Medicine County Sheriff, said the actions taken by sheriff's deputies and a Granite Falls firefighter undoubtedly saved lives and prevented injury, both to the bus driver and to motorists on the highway.

The bus driver, identified as Brian Fuller, 70, of Renville, appeared to have suffered a medical emergency while behind the wheel. He was taken by Granite Falls Ambulance for evaluation and treatment at the Granite Falls Hospital. The bus is owned by the Renville County West School District.

The incident unfolded Wednesday afternoon after the Yellow Medicine County 911 center received several calls about a school bus that had crashed into some vehicles in Granite Falls and was headed west on Highway 212. Deputies caught up with the bus two miles outside of town. At that point it was on the wrong side of the road and traveling at about 40 mph, Flaten said.

Deputy Sheriff Eric Diekmann was able to get past and in front of the bus and activate his vehicle's emergency lights to warn oncoming traffic. Flaten said.

Wayne DeBlieck, chief deputy, followed behind to radio information to the 911 dispatch center and other responding vehicles. Officers were able to observe the driver was experiencing some type of medical incident and that there appeared to be no passengers on the bus.

Diekmann managed to get close enough with the rear of his squad car to bump the bus, using his brakes to slow it down, according to Flaten. Once the bus was almost stopped, Granite Falls firefighter Greg Meyer, who was following in his personal vehicle, was able to open the driver's side door of the bus, stop it and put it into park, Flaten said.

The sheriff said Meyer had witnessed the bus crash in Granite Falls and got in front of the bus with his flashers on to warn oncoming traffic. "His selfless actions made this very dangerous situation come to an end with nobody getting injured," Flaten said in a statement.

Flaten also had praise for Diekmann for his actions in helping avoid a collision between the bus and oncoming traffic.

The video released Thursday is from the dash cam in DeBlieck's squad car and was posted on the Yellow Medicine County Sheriff's Office Facebook page.

For five heart-stopping minutes, the bus rolls down the highway in the wrong lane, at times drifting toward the shoulder. Oncoming traffic, including a couple of semis, has to move onto the shoulder to avoid a crash. Sirens can be heard.

The video captures the moment when Diekmann maneuvers his squad car to slow the bus. Then Meyer dashes across the highway, pulls open the bus door and disappears briefly from view while bringing the vehicle safely to a halt.

As of mid-afternoon Friday, the dash cam video had been shared on Facebook almost 270 times.