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.

The charred soil left by the wildfires could create conditions ripe for mudslides because the rain, which will last into Monday, will just run off, forecasters said.

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