The fire began at around 1 p.m. on the center divider of Interstate 15 in the Cajon Pass. It quickly grew to more than 500 acres in two hours, jumping the freeway and burning chaparral in rolling hills that form the nearby San Bernardino National Forest and unincorporated areas of San Bernardino County, U.S. Forest Service spokesman John Miller said.
An evacuation was ordered as the fire moved northwest toward large ranch homes in the Oak Hills area. Fire crews were placed to defend the houses, Miller said.
"There's million-dollar homes up there," Victorville resident Tom Woods told KCAL-TV.
The Oak Hills area contains hundreds of recently built luxury horse properties spread over the hills, Woods said.
Woods said he could see a huge plume of smoke from his home 10 miles away.
The fire initially closed all freeway lanes, snarling traffic as drivers struggled to start their Labor Day weekend getaways. Northbound lanes were reopened with escort by the California Highway Patrol as the fire burned away from traffic lanes.
Television news reports showed plumes of white smoke and a long line of fire running over scrub-dotted ridges. Flames burned within yards of some homes.
Miller said a firefighter was hurt, but he didn't know the extent of the injury. One motorist suffered smoke inhalation.
About a dozen aircraft, including a DC-10 jumbo jet tanker, were called in to help fight the flames.
