Brandon N. McGlover, 32, of Temecula was detained Wednesday and charged with arson to wildland, the Riverside County Fire Department and Cal Fire said.
By late afternoon Thursday, it covered 7,500 acres - or just over 11 square miles - and was still 5 percent contained, according to the San Bernardino National Forest.
A house is covered in pink fire retardant as the Cranston Fire burns out of control near the town of Idyllwild in the San Bernardino National Forest on Wednesday.
The hot and largely dry weather will further enhance the risk of new blazes into the beginning of August.More news: Lakers add veteran Michael Beasley to revamped roster
Campgrounds in Idyllwild were also under evacuation orders, including Idyllwild Arts, Camp Maranatha, Idyllwild Pines, AstroCamp, Camp Emerson and Tahquitz Pines, according to the volunteer organization Mountain Disaster Preparedness, which runs the website idyllwildemergency.com.
Portions of Highways 74 and 243 are closed. More than 2,100 homes were evacuated in Idyllwild, Apple Canyon, Lake Hemet, Mountain Center, Hurkey Creek, along with the Camp Scherman Girls Scouts camp. Additional evacuations were in Mountain Center along McGaugh Road and McCall Park Road. Animals could be evacuated to the San Jacinto Valley Animal Campus at 581 S. Grand in San Jacinto.
The blaze has almost tripled in size overnight and was threatening areas west of Redding. Power outages were also reported, with about 3,800 customers in the Idyllwild area without electricity.
In Southern California, thousands remained evacuated as a suspected arson wildfire burned in the San Jacinto Mountains east of Los Angeles. The area is under an excessive heat warning through Friday evening, and the National Weather Service warns the temperature could reach the 100s.