Crews battling a massive wind-driven California wildfire that has torched nearly 800 buildings and charred 230,000 acres are bracing on Monday to protect communities menaced by flames along the state's scenic coastline.

The Thomas Fire ignited last week and is burning in Ventura and Santa Barbara counties, about 100 miles northwest of Los Angeles.

"Fire will continue to threaten the communities of Carpenteria, Summerland, Montecito and surrounding areas," the California Department of Forestry and Fire Protection (Cal Fire)said in a Sunday night update.

The Sacramento bureau of the National Weather Service said in a tweet that the Thomas Fire is now the fifth largest fire in California's recorded history.

@NWSSacramento #ThomasFire in SoCal is now the 5th largest fire in CA history according to @CAL_FIRE. Our office continues to support the response at @Cal_OES state operations center #cawx

Santa Ana winds and the rugged mountainous terrain have hindered firefighters as they battle the blaze, which has destroyed 790 houses, outbuildings and other structures and left 90,000 homes and businesses without power.

"A lot of these guys (firefighters) have fought a lot of fires in the past few months and are fatigued," said Fire Captain Steve Concialdi, spokesman for the Thomas Fire.

Concialdi said firefighters from 11 Western states are aiding firefighting efforts.

The fire is 10 percent contained, down from 15 percent on Saturday after it blew up on Sunday, growing by 56,000 acres in one day and making a run of 7 miles, Concialdi said.

Nearly 5,800 firefighting personnel are working on the blaze, Cal Fire said. The cost of fighting as of Sunday was nearly $34 million, the agency added. It is already the fifth-largest wildfire on record in California.