The first in a series of storms Thursday brought rain, mountain snow and concerns for debris flows in recent burn areas.
Though some rain was still falling in the late afternoon, mandatory evacuation orders in the Holy Fire burn scar in the Lake Elsinore was downgraded to voluntary at 4 p.m.
The voluntary warning remained in effect for the following flood zones: Amorose, Alberhill, Glen Eden, Glen Ivy-A and B, Grace, Horsethief-A, Laguna-A, Maitri, McVicker-A, Rice and Withrow-A.
In the morning, Cal Fire Riverside officials had said residents of those areas "MUST GO NOW. Rainstorms carry the potential for dangerous debris flows that can send mud, boulders and trees crashing down hillsides."
The first storm made its way to Southern California from the Central Coast and was expected to bring about five hours of steady rain, according to the National Weather Service.
Peak rainfall rates were expected to range between 0.2 and half an inch of rain per hour, with up to an inch total.
"Minor and shallow debris flows are possible over recent burn areas, but the likelihood for damaging flows is slim," the weather service reported.
Around 3 p.m., NWS said that light to moderate rain would continue through the evening rush hours, then begin to taper off.
Officials also warned of downed trees, increased crashes and travel delays and rockslides on canyon roads.
Mud spilled onto lanes of Pacific Coast Highway by Deer Creek Canyon Road Thursday, according to Caltrans. Shortly after, all lanes of the roadway closed just north of the Ventura County line from Broad Beach Road to Las Posas Road, though they later reopened.
Another slide north of Yerba Buena Road extended the closure from Trancas Canyon Road to Las Posas in the early afternoon, Caltrans tweeted.
Caltrans workers will be monitoring conditions of highways 33, 23, 27 and PCH in Ventura County, officials said.
Another voluntary evacuation warning was in place in Orange County areas affected by the Holy Fire, officials said.
The voluntary evacuation in Orange County is for homes located within Trabuco Creek Rose Canyon and the Mystic Oaks / El Cariso areas.
Additionally, a flash flood advisory had been place in Orange County, southwestern San Bernardino County, western Riverside County and northwestern San Diego County until 2:15 p.m., according to the weather service.
A flood advisory was also effect in Los Angeles County until 2 p.m.
There were no mandatory evacuation orders in place in Santa Barbara, Ventura or Los Angeles counties, which also had areas that were recently ravaged by wildfires.
Zuma Beach in Malibu was closed Thursday morning because of lighting.
In a tweet, the Ventura County Fire Department asked residents to be prepared as the storm moves through that area.
The storm has prompted a winter weather advisory for Thursday evening in the mountains of Los Angeles and Ventura counties.
About 8 inches of snow is expected at elevations above 7,000 feet, with less expected above 6,500 feet. The snow is not expected to affect mountain passes, the weather service noted.
A reprieve from the first storm is predicted Friday, but a second, more potent storm is expected Friday night into Saturday.
The second storm will also bring gusty winds, and some lingering showers are possible through Monday night, according to the weather service.