Much-anticipated rain could be headed to drought-stricken Southern California this weekend -- but rainfall also brings the threat of landslides.

The Clay fire, which broke out Tuesday in a river bottom in Riverside County east of Los Angeles, quickly spread to nearly 40 acres. But by Tuesday night, crews had stopped its progress and were doing “extensive mop-up operations,” Riverside officials said. It was 40 percent contained as of 4 a.m. Wednesday, according to Cal Fire.