More rain fell Monday on parts of Southern California after causing mudflows over the weekend, helping firefighters but boosting the risk of toxic ash runoff in areas scorched by Los Angeles-area wildfires.

A slow-moving low-pressure system will linger over the Southwest, bringing steady rain through at least Monday.

The Los Angeles area is preparing for its first rain since wildfires first broke out weeks ago. But too much rain at once could bring its own set of significant issues.