Grantfire 100% contained at 484 acres

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The East Contra Costa County Fire Protection District battled up to seven vegetation fires Wednesday afternoon, which have destroyed several barn-like structures.

The wind-driven wildfires burning along the Alameda-Contra Costa county line were 80 percent contained as Thursday morning and have burned 500 acres, according to Cal-Fire. The first one was reported around 1 p.m.

Officials say the 'Grant Fire' is burning near Grantline Road and Mountain House Road in the Altamont Area. The fires are primarily burning east of Byron Highway, in the vicinity of the Clifton Court Forebay, which is a reservoir in the San Joaquin River Delta region of eastern Contra Costa County.

Winds in the area Wednesday evening were estimated at 30 to 40 mph, Cal Fire Battalion Chief Jonathan Cox said. 

"The wind is really our biggest hazard," Cox said. 

A couple of outbuildings have been destroyed, according to Cox. No one has been injured. 

Mountain House School has ordered a shelter in place for students and teachers.

Campos Family Winery told KTVU there was heavy smoke in the area but they were outside the immediate area of the fires. The winery was still open for business. 

Alameda County firefighters also helped fight the blazes. A Cal Fire helicopter is also assisting with water drops. 

California Highway Patrol reported a severe traffic alert on Bryon Highway between CA-4 and I-205. All lanes were closed in both directions. There is no estimated time to reopen the roadways.