HESPERIA, Calif. (AP) — Authorities say a fast-moving wildfire that swept across a Southern California freeway has destroyed 20 vehicles and burned five homes while threatening dozens of other structures.

Fanned by hot desert winds, the fire started along Interstate 15 – the main road to Las Vegas – and torched the vehicles as motorists fled on foot to safety. No serious injuries have been reported.

The fire spread quickly, growing to 3,500 acres and threatening the rural community of Baldy Mesa north of the freeway.

An evacuation center was set up at the local high school.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP’s earlier story is below.

A fast-moving wildfire swept across a freeway Friday in a Southern California mountain pass, torching at least a half-dozen cars and a tractor trailer as motorists abandoned their vehicles and ran to safety. There were no confirmed injuries, authorities said.

The fire fanned by hot desert winds burned on both sides of Interstate 15. The main highway between Southern California and Las Vegas was crowded with weekend travelers.

Dozens of vehicles were abandoned and hundreds of others turned onto side roads to get away from the flames as water-dropping helicopters flew over the Cajon Pass area about 55 miles northeast of Los Angeles.

Motorists stuck on the road described a harrowing scene.

“It’s crazy, you’re watching black clouds and white clouds of smoke, there’s a ridgeline off to my right … and it looks like any second flames will come over the ridgeline,” Chris Patterson, 43, said from his vehicle.

It’s not uncommon for wildfires to reach freeways in California. It was unclear, however, why dozens of cars were caught along Interstate 15, forcing frightened people to flee on foot along the side of the road.

U.S. Forest Service spokesman Uriah Hernandez said no injuries had been confirmed.

The agency said the fire had burned at least 2,000 acres and was threatening the rural desert community of Baldy Mesa. Some areas were evacuated.

Melissa Atalla said she could see the flames from her gas station in Baldy Mesa.

“People are spectating from our parking lot, running around getting water and beer. It’s chaos,” Atalla said. “One man came in and said, `Oh my, my house is getting burned.'”

The fire led authorities to shut several freeway lanes, causing traffic to back up for miles.

California Highway Patrol spokesman Steve Carapia said 50 to 75 vehicles were left abandoned on the freeway.

Raquel Martinez, 34, was traveling to Las Vegas with her husband for the weekend when they got stuck in northbound traffic on the I-15 for about an hour.

The sky darkened to black. As they drove by, cars were covered in “pink powder” – or fire retardant. Cars meanwhile were being redirected up narrow twisty emergency lanes from the southbound side headed north.

“I haven’t seen a fire that big and so close to us. It really was huge,” Martinez said.