A brush fire that started during a Southern California heat wave grew to more than 2,300 acres over the weekend near the Cahuilla Indian Reservation in Riverside County.
The Bonny Fire was 20-percent contained Monday morning. The fire started Thursday on the edge of the Cahuilla Indian Reservation south of Aguanga.
The fire in steep and rugged terrain threatened 786 structures and destroyed one outbuilding. Full containment isn't expected until Aug. 7, but firefighters noted this week's weather forecast might affect containment efforts.
Get top local stories in San Diego delivered to you every morning. Sign up for NBC San Diego's News Headlines newsletter.
"Current weather patterns and a chance of thunderstorms through Tuesday could increase the risk of erratic fire behavior," the fire department statement said.
Firefighters planned to continue working to improve fire lines, cooling hot spots and digging more containment line around the fire perimeter, officials said.
More than 2,000 firefighters are battling the fire. Seven helicopters and several air tanker also responded.
An evacuation order remained in effect for the area north of the San Diego County line, east of Bonny Lane, south of Bowers Road, Bailey Road and Ramsey Road and west of Anza Borrego State Park.
An evacuation warning was also issued at noon Saturday to include the area of south of La Cima Road/Indian Paint Brush Road, west of Anza Borrego State Park, north of the San Diego County line and east of Spanish Spur Trail, according to the Riverside County Fire Department.
A care and reception center was established at Hamilton High School in Anza. The county Department of Animal Services stationed personnel at the location to assist with displaced animals, who were being housed at the San Jacinto Animal Campus at 581 South Grand Ave.
The cause of the fire was under investigation.