Evacuations were ordered when the Hawarden Fire grew to more than 400 acres (160 hectares) and spread to a residential area of Riverside, about 60 miles (95 kilometers) east of Los Angeles.
Aerial footage from KABC-TV showed at least three houses burning. The fire sparked Sunday had no containment and was threatening several other homes, the City of Riverside Fire Department said.
Multiple other small fires were burning across inland Southern California as temperatures reached triple digits (37 Celsius) in some areas.
Far to the north in Colusa and Lake Counties, evacuations were ordered Sunday for remote homes threatened by the Ridge Fire. The blaze broke out Saturday and grew to more than 4 square miles (10 square kilometers). It was 15 percent contained on Sunday.
