Clay Fire initially started 5 p.m. Jan. 21 in Riverside County. After being active for 37 hours, it has burned 39 acres. As of Thursday morning, 70% of the fire was brought under containment by a crew of 50 firefighters. The cause of it remains under investigation.

The Clay Fire was one of several fires that broke out in Southern California Tuesday as parts of the region sees red flag warnings through Thursday.

Firefighters in Riverside County battled a wildfire that erupted in the Santa Ana river bottom Tuesday night, prompting evacuation warnings for residents in nearby homes. The Clay Fire, first reported at 5 p.