Mandatory evacuations of 50,000 residents have been ordered Saturday for Healdsburg and Windsor due to concerns that the Kincade Fire will be fueled overnight by forecasted gusty winds.
The Sonoma County Sheriff's Office, along with Cal Fire and county officials said residents of those areas should leave no later than 4 p.m.
"We are evacuating because this fire is very dangerous and it's expected to move toward Windsor and Healdsburg this evening," Sonoma County Sheriff Mark Essick said during a press conference Saturday morning.
High winds have the potential to trigger erratic fire behavior, ignite new fires and knock down timber across roads and power lines, Cal Fire officials said.
Sustained winds of 40 mph, with gusts of 60 to 80 mph are expected Saturday night, peaking from midnight through sunrise, fire officials said.
The Kincade Fire grew overnight to 25,455 acres and was 10 percent contained as of Saturday morning, Cal Fire officials said.
No fatalities have resulted from the blaze, but 49 structures have been destroyed and another 23,500 are threatened.
Dominic Foppoli, Mayor of Windsor, urged residents to evacuate quickly.
"Do not take this warning lightly. We need everyone to evacuate," Foppoli said at the press conference. "We are going to get through this. Treat all of your neighbors as though they are your own family."
David Hagele, Healdsburg Mayor, said residents should not linger and avoid becoming a hazard to themselves and firefighters.
"It's time to drop things, pack and go in a calm and orderly manner," he said.
A map of the areas ordered for evacuation, and two other areas that are under a warning is available on the Sonoma County website.
Anyone with difficulty evacuating is asked to call the Sonoma County sheriff for assistance at 911.
Two thousand people have already been evacuated due to the Kincade Fire and all roads east of state Highway 101 in the Geyserville area are closed.
Residents of the area evacuating are asked to drive south, to evacuation centers at the Santa Rosa Veterans Memorial Building, 1351 Maple Ave. in Santa Rosa; the Petaluma Veterans Building at 1094 Petaluma Blvd. in Petaluma; and the Petaluma Fairgrounds at 100 Fairgrounds Drive.
The Sonoma County Fairgrounds is available to house large animals only, at 1350 Bennett Valley Road in Santa Rosa.
A Red Flag warning is in effect for the area from 8 p.m. Saturday to 11 a.m. Monday.