LOS ANGELES — 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.

Rain fell on parts of Southern California on Sunday and the scattered showers were expected to continue overnight, boosting the risk of toxic ash runoff in areas scorched by Los Angeles-area wildfires.

Southern California is about to get its first significant rainfall in months, bringing desperately needed relief after dry conditions and hazardous winds fueled a series of wildfires in January. The rain could start as early as Saturday afternoon and last through Monday night with the heaviest rain coming on Sunday,