A brush fire in Riverside burned 70 acres Thursday morning and prompted evacuation orders for nearby residents, which were later lifted, authorities said.
The blaze, dubbed the Riverbottom Fire, was expected to be fully contained late Friday evening after containment rose to 50% Thursday evening, the Riverside Fire Department said.
Officials suspect the flames erupted due to an unattended encampment.
The fire was reported at 4 acres about 11:40 a.m. near the Santa Ana bike path in the area of Grand Avenue, according to a City of Riverside Fire Department alert. It quickly grew to 68 acres and was 0% contained around two hours later, Riverside Police Department Officer Ryan Railsback said.
By 1:26 p.m., fire officials reported a "significant increase in fire activity" and announced that mandatory evacuation orders were in place for residents on Old Ranch Road and Park Cliff Court.
At about 2:45 p.m., authorities had gained 20% containment of the fire, which was at 70 acres, and all evacuation orders were lifted.
"It was a minor fire from the beginning, but then a significant increase when the weather changed we had winds that pushed it into the neighborhood and that prompted evacuations," Capt. Brian Guzzette, of the Riverside Fire Department told KTLA. "Fortunately now winds have died down and it's in some favorable fuel conditions, there's quite a few mutual resources on scene and so there's significant improvement on the fire."
The Santa Ana bike path was closed down from Ryan Bonaminio Park to Anza Narrows Park, according to the department.
No injuries were reported and no structures were damaged in the fire.
A total of 221 firefighters responded to the scene, officials said.
KTLA's Nancy Fontan contributed to this report.