Police in California have arrested a man on suspicion of starting the Line Fire, a massive wildfire that has burned more than 34,000 acres (53 square miles) across the state.

Justin Wayne Halstenberg, a 34-year-old resident of Norco, California, was arrested Tuesday on arson charges and is being held pending bail, officials said.

The Line Fire is one of three major wildfires that have ignited in Southern California in the past week and have raged out of control, leaving firefighters struggling and thousands of homes under threat.

By Wednesday morning, the fire was 14% under control.

Police have not released details about how Mr. Halstenberg allegedly started the massive fire in San Bernardino County, about 60 miles (96 kilometers) east of Los Angeles.

Thousands of people had to leave the area and the fire threatens more than 65,000 buildings.

CalFire officials say the fire is moving up steep slopes, making access difficult, especially near the Big Bear area.

The fire was fanned by high winds and dry conditions, but firefighters hope cooler weather later in the week will aid their work.

The threatened buildings, both residential and commercial, are located in approximately 13,300 areas where an evacuation order is currently in effect.

Blaine Bacher, one of the evacuees, said the first thing he took from his home in Arrowbear Lake was his mother’s ashes.

Mr Bacher told the BBC on Wednesday he has no idea whether his house is still standing.

“This house is more than just walls and a roof,” he said.

“My mother passed away in that house. I held her hand for her last breath in that house. She and my stepfather built and raised me and my sister in that house. It’s priceless.”

There have been no reported deaths or structural damage from the Line Fire. However, photos obtained by the Los Angeles Times appear to show that at least one building in Running Springs, a community in the San Bernardino Mountains, has been destroyed.

Nearly 2,000 firefighters are battling the blaze. The California National Guard is also supporting the fire department with crews and aircraft, including helicopters to drop buckets of water.

Another blaze—the Bridge Fire—is raging in the Angeles National Forest. It started on September 8 and has exploded in size to 46,700 acres (71.8 square miles).

According to CalFire, the cause is under investigation.

Images of the fire are circulating on social media, showing ski lifts at the Mountain High ski area in California going up in flames.

On Monday, a third wildfire broke out: the Airport Fire.

It is burning in an area between Orange and Riverside counties and is 22,300 acres (34.8 square miles) in size.

According to reports, several homes have been destroyed in the fire at the airport, but authorities have not yet provided details.

Large plumes of smoke from the fire were reportedly visible as far away as Los Angeles Airport.

The Los Angeles Times reported, citing sources within the Orange County Fire Authority, that the fire was likely started by a spark from heavy equipment used by road workers in the area.

Both the fire on the bridge and the fire at the airport were 0% under control on Wednesday morning.

The fires came amid a heat wave in Southern California that has broken all previous temperature records. Some areas have seen temperatures reach 110 degrees Fahrenheit in recent days, but temperatures are expected to drop for the rest of the week.