More than 17,000 firefighters struggled Friday to contain dozens of large fires that have burned huge swaths of land and destroyed hundreds of buildings across 10 US states, with parched California especially hard hit.

On Thursday alone, 31 fires burned nearly 400,000 acres (162,000 hectares) in the affected areas, including seven blazes in California and six in Idaho, according to the National Interagency Fire Center (NIFC).

In California, the Bluecut Fire in the mountains of the Angeles National Forest near Los Angeles has swallowed up 37,000 acres in three days and is just 26 percent contained.

More than 82,500 people are under evacuation warnings, and 34,500 homes are affected in the evacuation zone.

"There is imminent threat to public safety, rail traffic and structures in the Cajon Pass, Lytle Creek, Wrightwood, Oak Hills and surrounding areas," the NIFC's InciWeb said.

"Please follow the evacuation instructions, as this is a very quickly growing wildfire."

Authorities say 96 homes have burnt, along with 213 additional buildings.

No victims have yet been reported, but search dogs are being deployed to search for possible bodies in burned-out buildings.

Three people have been arrested for trying to loot evacuated homes, according to the San Bernardino County Sheriff's Department.

Further north in California, massive blazes were burning through forests near Santa Barbara (Rey Fire), San Luis Obispo (Chimney Fire) and the tourist hub of Big Sur, where the Soberanes Fire has charred 81,400 acres.

Nearly 1,000 homes have been destroyed and seven people have died since the start of the year due to fires in America's most populous state.

Despite a growing number of large fires in recent weeks, this year's fire season is still the least destructive in recent years.