A two-alarm fire tore through the service area of a Clovis car dealership late Friday afternoon, sending a mushroom cloud of black smoke skyward that could be seen from miles around.

No one was injured in the fire at Future Ford of Clovis, just west of Willow Avenue. The cause was undetermined, and an investigation was underway Friday night.

The fire spread to more of the 100,000-square-foot building in part because heavy evening traffic and onlookers blocked the path of arriving firefighters, who needed the help of police to clear their way, said Clovis Fire Battalion Chief Steve Henry.

"Fires this size grow four times the size every minute delayed," Henry said.

Backups were reported after surrounding streets were closed to traffic. At one point, the Highway 168 on- and off-ramps to Shaw Avenue were shut down.

"I was on my way to Visalia for the weekend and there was so much traffic that I had to go all the way to Shields to get on the freeway," said George Gonzalez, a Fresno State student.

Forty-three firefighters from Clovis and Fresno fought the fire for an hour before bringing it under control.

"I saw huge clouds of smoke from about two to four miles away, and from the diameter of the bottom of the smokestack, I thought it would be really big," said Brandon Mazgedian, an auto detailer from Clovis. "I was thinking it was the Ford store, and sure enough it was."

Mechanics and other workers were in the service building when the fire erupted. All escaped without injury.

By the time firefighters responded to the initial 4:30 p.m. call, 40% to 50% of the building was engulfed in flames. It was not equipped with sprinklers, Henry said.

"I heard several large explosions inside that could have been from gas tanks exploding," he said.

It took about 30 minutes for firefighters to stop the blaze from advancing, and nearly 80% of the building was destroyed by the time the fire was contained.

The total amount of damage is estimated at $80,000, said Clovis Fire Department spokesman Chad Fitzgerald.