Police were alerting residents in fire-scarred neighborhoods along the San Gabriel Mountains late Tuesday that rain cells expected to hit the area could cause mudslides.
Advisories were issued by the Azusa and Glendora police departments for neighborhoods north of Sierra Madre Boulevard where the Colby fire burned nearly 2,000 acres in January.
Several storm cells were expected around 1 a.m. Wednesday and could drop 0.25 to 0.50 inches of rain, officials said. The showers could last as long as 30 minutes each.
"The cells may also create lightning strikes," the Azusa Police Department said.
Shortly before 10 p.m., heavy showers were reported in western Ventura County and were moving eastward, according to the National Weather Service.
The agency was predicting cold and wet weather through Wednesday. The storm, which generated in the southern Gulf of Alaska, could drop 0.25 to 0.75 inches of rain across the Los Angeles area, the Weather Service said.
Three to six inches of snow could fall at elevations above 4,500 feet and cause hazardous driving conditions on mountain roadways, officials said.