A fire broke out Thursday in the Santa Ana River bottom near downtown Riverside, burning roughly four acres in less than an hour. but no homes or other structures were immediately threatened.
The non-injury brush fire was reported at 10:25 a.m. just northeast of McLean-Anza Narrows Park, according to the Riverside Fire Department.
Multiple crews from the city and Riverside County were sent to the location and encountered flames in thick brush along the river bottom.
Firefighters were making slow progress encircling the brusher because of the location and density of foliage, according to reports from the scene.
The cause of the fire was under investigation.