Fires in California: Grim search of charred homes

US couple drive through California wildfires. Source: Andre Epstein and Neda Monshat

Death toll rises to 35 as wind-driven blazes merge in Northern California.

Fire officials in Northern California reported further headway against the most lethal outbreak of wildfires in the state's history, as the death toll rose to 35 and teams with cadaver dogs combed ruins for human remains.

The wind-driven blazes, which erupted last Sunday night in the heart of California's renowned wine country north of San Francisco, have destroyed an estimated 5700 homes and businesses and forced the evacuation of at least 25,000 people.

With 235 people still missing and rubble from thousands of incinerated dwellings yet to be searched, authorities have said the number fatalities from the North Bay fires would likely climb higher.

Even as firefighters gained more ground during better weather yesterday, they braced for a return of higher temperatures, lower humidity and strong, gusty winds that could increase the threat to communities.

By yesterday, 17 major wildfires -- some encompassing several smaller blazes merged together -- had consumed nearly 90ha of dry brush, grasslands and trees across eight counties.

Officials have said power lines toppled by gale-force winds the first night may have sparked the conflagration, though the official cause remained under investigation.

Much of the devastation centred in and around the Sonoma County town of Santa Rosa, where neighbourhoods were reduced to landscapes of grey ash, smouldering debris and burned-out vehicles.

Some victims were asleep when flames engulfed their homes, and many survivors had only minutes to flee.

The 35 confirmed fatalities surpass the 29 deaths from the Griffith Park fire of 1933 in Los Angeles.

Sonoma County Sheriff Robert Giordano said 45 search-and-rescue teams and 18 detectives had been deployed to scour obliterated neighbourhoods for more victims.

The year's wildfire season is one of the worst in history in the United States, with nearly 3.5 million hectares burned, according to the National Interagency Fire Centre.

- AAP