Justin Wayne Halstenberg, 34, of Norco, was arrested for allegedly starting the fire, according to the San Bernardino County Sheriff's Department. He was being held on $80,000 bail.
Information on how he allegedly started the fire and what led investigators to him was not immediately available.
A portion of Big Bear was placed under an evacuation order Tuesday afternoon as the fire continues to burn and spread near Highland and other mountain communities.
According to the sheriff's department, residents in the area from the Big Bear dam east to Wildrose Lane and the south shoreline south to Bluff Lake Basin are being told to leave. There's also an evacuation order issued for communities like Running Springs, Forest Falls, Angelus Oaks and Wrightwood.
Portion of Big Bear under evacuation order as Line Fire near Highland burns more than 27,000 acres
Highway 330 in Highland, which is closed to the public, is one of the main roads being used to get resources up into the mountains. Two of the main routes in and out of Big Bear - Highway 18 from the west and Highway 38 through the east - are both closed.
As of Tuesday afternoon, most residents have already evacuated, but as the fire gets closer to the mountain communities, people are running out of time.
Interactive map from Cal Fire
This interactive map from Cal Fire shows the latest evacuation orders and warnings, plus road closures and detours:
This 3D map, also from Cal Fire, shows the breadth of the fire zone, and it includes the latest acreage.
Crews making progress
Cal Fire said crews have made good progress thanks to better weather conditions.
"Conditions have started to stabilize as far as the thunderstorms go, we don't have that expected for [Tuesday,]" said Brent Pascua, a battalion chief with Cal Fire.
Firefighters in Angelus Oaks made their way through steep and rugged terrain Tuesday, using chainsaws and other tools to make defensible space. The Line Fire is slowly pushing to the northeast toward Big Bear, but it's moving even closer to Mountain Home Village and Highway 38.
The U.S. National Guard is helping protect homes from any potential looters. Firefighters have also come from all over the country to help.
"It's like a family, one giant family across the United States," said Benjamin Brick, whose team came to San Bernardino County from New Jersey. He said they're taking note of the extreme fire behavior his crew sees when they come west.
"They burn fast, very fast compared to back home," he said.