In Southern California, five people were trapped Monday inside a smoky canyon near Los Angeles as firefighters struggled to beat back a 20-mile-long wall of flames that had already destroyed 53 homes, including some forest cabins, and was threatening 12,000 more structures, including the famed Wilson Observatory, northeast of Los Angeles. Two firefighters were killed near Acton on Sunday when their truck went off a road.

In Mariposa County, 50 homes were evacuated Monday as flames crackled over 7 square miles in Yosemite National Park. About 2,000 homes were threatened in San Bernardino County, and evacuations were ordered in Oak Glen, a scenic community amongst apple orchards about 90 miles east of Los Angeles.

In all, nearly 6,000 firefighters were battling seven major wildfires between Siskiyou County and Riverside County on Monday.

Soaring temperatures and tinder-dry vegetation caused the onslaught all across the state, according to Del Walters, director of the California Department of Forestry and Fire Protection.

"All of the vegetation is very volatile at this point, and the last few days we've had very, very low humidity," Walters said. "We've been seeing a lot of fires with a rapid range of spread. Once they get going like that, they put a lot of embers into the air that can ignite homes, which is what we saw in Auburn."

The 49 Fire, named after Highway 49 in the Sierra foothills town of Auburn, blackened only 340 acres - compared with the more than 105,000 acres of the Station Fire in Los Angeles County. But there were dozens of homes in its path.

Among those who lost homes was Tami Higgs.

"We lost everything," said Higgs, whose daughter fled barefoot from their burning home, saving only the family's two dogs. The cat is missing, she said.

As Schwarzenegger toured the devastation in Auburn on Monday, walking past the charred hulks of cars and the smoldering ruins of homes, he spotted Higgs sitting on a sidewalk curb crying.

"We are here for you and we are sorry you had this loss," Schwarzenegger told Higgs as he wrapped her in a bear hug.

The 49 Fire was 70 percent contained as of Monday.

The largest fire of all was the Station Fire, which started in the Angeles National Forest on Wednesday and nearly doubled in size overnight Sunday. By Monday evening, it had scorched 105,296 acres and was racing toward the communications and astronomy centers atop Mount Wilson, where firefighters were making a desperate attempt to save the historic observatory.

"It's one of the worst situations I have ever seen," said Walters, who authorized the use of a third air tanker Monday to fight the fire, which he said is unprecedented. "You've got very, very rugged wildland surrounded by urban and suburban areas. There are no good places to stop that fire."

The fire, which was only 5 percent contained Monday, burned 21 homes to the ground as it crackled through the rugged foothills northeast of Los Angeles, fed by brush that had not burned for 40 years, fire officials said.

At least 6,600 homes were under mandatory evacuation orders as more than 2,500 firefighters, 20 helicopters and several air tankers battled the flames throughout the day. Neighborhoods in Glendale, Pasadena and other smoke-choked cities and towns north of Los Angeles were emptied of people as the flames converged.

Los Angeles County sheriff's spokesman Steve Whitmore said five people who refused to evacuate were trapped at a ranch near Gold Creek. Sheriff's helicopters were unable to reach them amid the intense flames and their fate was unknown Monday afternoon.

"Those people were told to get out two days ago," Whitmore told the Associated Press. "Now we are putting our people in danger to get them out."

The fire also stranded 64 leopards, lions, tigers and cougars at the Roar Foundation Shambala Preserve, near Acton. Firefighters were using the sanctuary's 22,000-gallon water tank to battle the flames.