The fire in Thermal, about 10 minutes away from the Coachella Music Festival, broke out around 9:40 p.m. Thursday near Avenue 62 and Jackson Street, according to the Riverside County Fire Department.
It was initially reported as a 5-acre vegetation fire burning at a rapid rate of spread, and it spread to nearly 30 acres by Friday morning.
Crews said they were able to establish control lines around the fire, but they would remain on scene to fully contain it. Winds in the area were strong overnight, but they're expected to weaken throughout the day.
Officials say about nine threatened residential structures were under evacuation orders. An evacuation center was established at the Desert Mirage High School gym on Avenue 66.
A firefighter was hospitalized with minor injuries sustained fighting the flames, and one civilian suffered unknown injuries.
The cause of the fire is under investigation.