California emergency officials on Thursday ordered hundreds of people to evacuate a town north of San Francisco, and nearly 200,000 were without power in the state, as a growing wildfire spread in Sonoma County. Driven by strong winds, the Kincade fire engulfed some 10,000 acres (4,047 hectares) by Thursday, according to the California Department of Forestry and Fire Protection. The Sonoma County Sheriff issued a mandatory evacuation order for the town of Geyserville, home to almost 900 people. An evacuation warning for the town of northern Healdsburg remained in place. As crews battled the fast-burning fire, footage and images posted on social media by local reporters showed the smoldering wreckage of destroyed homes. Separately, officials were responding to a vegetation fire in Annadel State Park southeast of Santa Rosa, the local fire department said. Large parts of California were under red-flag alerts this week, suggesting a heightened risk of fire, amid high temperatures and powerful winds, officials said. About 196,000 customers were without power in the state on Thursday morning, according to power outage.us. More than half a million homes and businesses in the state could lose power this week as utilities, including Pacific Gas & Electric and Southern California Edison, cut off electricity as a preventive measure against wildfires. Nearly 300,000 customers in seven counties, including Los Angeles, San Bernardino and Ventura in southern California, were under consideration for Public Safety Power Shutoffs, Southern California Edison said. National Weather Service meteorologist Marc Chenard said the worst of the winds would arrive later in the day and into Friday. "It looks like at its worst, southern California will see wind gusts of 55 miles per hour (89 kph). Down in some of the coastal areas, the winds could reach 75 miles per hour (121 kph) later today," he said. Power lines could be knocked down, potentially igniting fires among arid trees and vegetation, according to earlier forecasts. Bankrupt Californian power producer PG&E cut off electricity to more than 730,000 homes and workplaces in northern California earlier this month to try to reduce the risk of wildfires amid extremely windy and dry weather. Chenard added that northern California could experience dangerous wind gusts of up to 45 mph (72 kph). "This is not going to abate until at least this weekend," he said. — Reuters