The latest inferno began with the Glass Fire and two subsequent fires merged with it, burning 44 sq km, according to the California Department of Forestry and Fire Protection, or Cal Fire.
More than 53,000 people in Sonoma and Napa counties were under evacuation orders, said Daniel Berlant, assistant deputy director with Cal Fire. Many more have been warned that they may have to flee.
Paul Lowenthal, another Cal Fire spokesman, said more than 13,000 homes were threatened in Santa Rosa alone.
The causes of the new fires were under investigation.
So far this year, more than 8100 California wildfires have scorched 14,970 sq km, destroyed more than 7000 buildings and killed 26 people.
- AP