An up-and-coming Penngrove sprint car racer crashed during warm-ups at the Marysville Raceway Park on Saturday, leading to the deaths of two people.

Marcus Joseph Johnson, 14, of Santa Rosa died at Rideout Memorial Hospital in Marysville, where he had been taken by ambulance after the crash, according to a Yuba County Sheriff's Department spokesman, and Dale Richard Wondergem, 68, of Grass Valley, died at the track.

Marcus Johnson and the 17-year-old driver of the sprint car, Chase Johnson, of Penngrove, were reportedly cousins.

Chase Johnson was driving hot laps -- a practice routine that is a crowd favorite -- when things went terribly wrong as he approached the first turn of the quarter-mile banked clay oval, a witness said.

"It really seemed to me that something went wrong with the car because he wasn't able to make the turn," said Steven Blakesley, a motorsports announcer who was standing about 30 feet away from the accident.

Johnson's car shot off a ramp from the track, glanced off some tractor tires and into a concrete barrier upon which the victims were apparently sitting, Blakesley said.

"He went off the off-ramp at full speed, so I estimate it at 90 mph," Blakesley said. "My original concern was for Chase himself because of the impact, but I guess he was able to walk away."

Johnson is a Petaluma High senior and a fourth-generation race car driver, according to his website.

The website introduction said that in 12 years of racing he has won more than 140 major events and seven championships. Last year was his fourth in a winged sprint car, the website said.

"He's a very young, focused, quiet driver, a very talented driver," Blakesley said. "You're talking about a driver who's very experienced. He's young, but he knows what he's doing out there."

There were perhaps 10 other cars on the track at the time, Blakesley said, and it didn't appear that there had been any contact prior to the crash. He said that had Johnson veered to the left, he would have entered a pit area starting to fill with crews.

"It's a godsend he didn't," Blakesley said.

The crash hushed the raceway, where the crowd had reached about 1,000 more than a hour before the racing was to begin, Blakesley said.

Tyler Wolf of Redding, a 20-year-old race car driver, was killed last October when he crashed during a race at the Calistoga Speedway.

In June, a Chico race car driver died from injuries he received when a tire he was inflating apparently exploded while he worked on it at the Silver Dollar Speedway.

"The sprint car thing, this year, from last year to now, has been about as difficult as you can imagine,. But they've all been unique circumstances, it's not one thing endemic to the sport," Blakesley said.

Sprint cars are small, high-powered cars that normally race on short dirt ovals.

Saturday's event, the California Sprint Car Civil War Series, was canceled.

The track is a mile east of Marysville near the town of Linda.