By Demian Bulwa

Several out-of-control wildfires were burning in Napa and Sonoma counties early Monday morning, prompting mass evacuations of many neighborhoods and at least one Wine Country resort as firefighters sought to halt the advance of the flames amid high winds.

The National Weather Service said the fires, which caused power outages and blanketed much of the Bay Area in smoke, were being fanned by strong and dry northeast winds. There was no immediate information on potential damage and injuries.

Cal Fire, the state agency, said the Atlas Fire in Napa County was near Atlas Peak Road and had blackened at least 200 acres. The area is northeast of the city of Napa and the Silverado Trail.

A second blaze was to the northwest, near Calistoga, and also caused evacuations.

Meanwhile, in Santa Rosa, evacuations were ordered for residents and businesses in the Skyfarm, Fountaingrove Parkway and Montecito Heights areas, according to the Police Department. Evacuees were directed to the Finley Community Center on West College Avenue and Stony Point Road.

In Napa County, guests of the Silverado Resort and Spa on Atlas Peak Road said they had been hurriedly evacuated as flames approached. The resort had hosted the Safeway Open, a PGA Tour event, which ended Sunday.

The Napa County Sheriff's Office said all residents from Atlas Peak Road east to Circle Oaks near Highway 121 should leave their homes. Earlier, officials said Soda Canyon residents should evacuate.

Evacuation centers were set up at the Napa County Fairgrounds at 1435 North Oak St. in Calistoga and CrossWalk Community Church at 2590 First St. in Napa.

At the same time, the Sheriff's Office said evacuations were under way near Calistoga, from Knights Valley to Tubbs Lane, because of the other blaze. Residents there were directed to the Napa County Fairgrounds.

In Sonoma County, authorities were also responding to multiple wind-driven fires.

The Sonoma County Sheriff's Office said fires had broken out at Mark West Springs and Riebli roads in Santa Rosa, at Shiloh and Conde roads in Windsor and at Highway 116 and Fredericks Road in Sebastopol.

"Local fire departments are on scene and we will notify you if any evacuations are called for," the Sheriff's Office said. "The strong winds are making these fires difficult."

Officials said Sonoma County emergency dispatchers were being "overwhelmed by 911 calls" from residents smelling smoke, adding, "Please only call 911 if you see actual unattended flames."

Authorities in Marin and San Francisco counties made the same plea, asking residents who smell smoke not to call 911 unless they see flames.

There was no immediate information on potential damage or injuries. Check back for updates.

(c)2017 the San Francisco Chronicle