A house sustained heavy damage in a fire that also charred 4.3 acres of grassland in Alamo on Saturday afternoon, according to the San Ramon Valley Fire Protection District.

The situation unfolded just before 3 p.m. Saturday in the Alamo Ranch Estates on Alamo Ranch Road, a residential community with hilly terrain just west of Interstate 680 near the Stone Valley Road exit.

SRVFPD crews arrived to find one house in flames and nearby vegetation on fire, according to battalion chief Dan McNamara. The cause and point of origin of the fire remain under investigation.

Firefighters used a ground attack as well as support from a Cal Fire helicopter unit to knock down the flames in the hills amid hot weather and a slight breeze, stopping forward progress after about two hours, McNamara said. There were also reports on social media of civilians in the area working to prevent spread to other nearby homes.

The 4.3 acres of vegetation that burned was located mainly among the neighborhood's steep and long driveways, and all of the properties in that area had the recommended amount of defensible space established around the houses, according to the battalion chief.

McNamara said the response was "successful in terms of the firefight and with residents and their defensible space. We had multiple units from Alameda County Fire and Contra Costa Fire assisting as well."

SRVFPD officials confirmed late Saturday night that one firefighter was taken to a nearby hospital with a "minor heat-related injury."