Napa and Sonoma County wildfires on October 9, 2017

Media: San Francisco Chronicle

Several massive wildfires were burning out of control in Napa and Sonoma counties early Monday morning, forcing the evacuation of neighborhoods and at least one Wine Country resort and the shutdown of major roadways as firefighters sought to halt the advance of infernos driven by powerful winds.

There was no immediate information on damage and injuries — nor an explanation for the sheer number of fires — but structures including homes were burning in both counties, according to authorities and witnesses.

The series of fires began to ignite late Sunday and multiplied as the night went on, impacting four counties. In Mendocino County, authorities evacuated communities near Redwood Valley and Willits. And in Marin County, officials said just after 3 a.m. that a grass fire had closed Highway 37 between Highway 121 and Lakeville Highway.

All over the region, flames raced across fields and freeways and skies filled with embers and ash. The National Weather Service said the blazes, which caused power outages and blanketed much of the Bay Area in smoke, were fanned by strong and dry northeast winds.