Much-needed rain has begun to fall over Southern California, bringing relief to the drought-stricken region but also the threat of toxic runoff.

Rain was falling across Southern California on Sunday, bringing some relief to thousands of firefighters who have been battling multiple major wildfires in the LA area.

San Diego's dry conditions greatly increased the risk for wildfires. “We’ve been experiencing extreme fire behavior throughout Southern California as many have seen," said Rob Johnson, public information officer for CAL Fire.