Update, 8:10 a.m. Thursday: Cal Fire's latest summary of the Grant Fire, the series of blazes that broke out Wednesday afternoon south of Byron and west of Tracy:
The firefighting agency says the fire charred about 500 acres and was 80 percent contained Thursday morning. The fires destroyed one home, three outbuildings, three vehicles, a trailer and a boat.
There's no word yet on the cause of the fires.
Original post: Cal Fire ground crews and helicopters responded Wednesday afternoon to a series of wind-driven fires burning in far eastern Contra Costa and Alameda counties.
Cal Fire reported that it was fighting seven separate fires -- scattered in rolling, grassy terrain over a 10-mile stretch south of Byron and west and south of Tracy -- totaling about 500 acres. The fire agency dispatched both water-dropping helicopters and fixed-wing tankers to stop the blazes.
One of the blazes was burning on the western edge of Clifton Court Forebay, a holding basin for both the State Water Project's California Aqueduct and the federal Delta-Mendota Canal.
Live video from ABC7 showed that another fire appeared to have swept through an electrical facility with several dozen wind turbines.
Aerial images showed an undetermined number of structures were damaged or destroyed. Some roads in the area, including sections of Mountain House Road and Grant Line Road, were closed.
There was no immediate indication of the fires' cause.
This post will be updated.