REDDING • Nine people were reportedly missing as a monster wildfire in northern California burned unchecked yesterday after it killed two firefighters, destroyed hundreds of structures and sent thousands of frantic residents racing from their homes.

About 3,400 firefighters on the ground and in helicopters and airplanes battled the 19,500ha Carr Fire as it ripped through Redding, a city of 90,000 people, in California's scenic Shasta-Trinity area north of San Francisco.

More than 38,000 residents in Redding and elsewhere in Shasta County fled their homes as the fire began to gain speed and intensity last Thursday, destroying 500 structures and leaving Keswick, a town of 450, in smoldering ruins, California Department of Forestry and Fire Protection (CalFire) said.

The fire, which was just 3 per cent contained after igniting six days ago, has been fed by high temperatures and low humidity, which were expected to continue for at least the next week, said CalFire director Ken Pimlott.

"This fire is a long way from done," he said.

A bulldozer operator and a member of the Redding Fire Department were killed in the blaze. A Redding hospital said it had treated eight people, including three firefighters.

Nine people, including a woman and her two great-great grandchildren, were missing, a CBS news affiliate in Sacramento reported, citing local police.

The woman's husband told the station he left them at home to run an errand on Thursday night.

California has had its worst start to the fire season in a decade, with 117,248ha burned through to Friday morning, according to National Interagency Fire Centre data.

REUTERS