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