After weeks of windy and dry weather, rain has fallen in parched Southern California and is expected to aid firefighters who are mopping up multiple wildfires. But potentially heavy downpours on charred hillsides could bring new troubles such as toxic ash runoff.

The highest intensity rain was expected between 4 p.m. on Sunday and 4 p.m. on Monday, according to the service. Los Angeles and Ventura Counties were expected to get up to an inch of total rainfall, and up to three inches was forecast in the mountains around Los Angeles.

Some areas could get more than a half-inch of rain an hour later Sunday, the National Weather Service said. Showers could linger into Tuesday. Areas where the Palisades, Franklin, Eaton, Bridge,