(FOX 11 / CNS) UPDATE: Azusa has now also issued MANDATORY evacuation orders for residents on Ridge View Drive due to fears of mud and debris flows from the pending storm. Residents can use the same evacuation center being offered in Glendora at the Crowther Teen & Family Center at 241 W. Dawson Ave.
(FOX 11 / AP) Southern California got an overnight soaking Thursday as residents prepared for a second, more powerful storm that could bring heavier rain and prompted fears of mudslides in communities along fire-scarred foothills.
The weather system moved down from Northern California, bringing up to an inch of rain in drought-stricken coastal and valley areas of Los Angeles County, and more in the mountains. About an inch of rain fell earlier around the San Francisco Bay Area.
Authorities urged commuters to drive with caution as some Los Angeles-area freeways saw water pooling in lanes. An early-morning rockslide was cleared from a Malibu canyon thoroughfare and no injuries were reported.
The storm — and the far larger one expected to arrive Friday — brought worries and recommended evacuations in some areas in the suburbs of Glendora and Azusa about 25 miles northeast of Los Angeles, because they sit at the foot of the steep San Gabriel Mountains where a wildfire last month stripped nearly 2,000 acres where water could now pose a danger.
‘‘Residents located near burn areas should be alert for the potential of mud and debris flows Friday through Saturday,'' forecasters said.
Glendora on Wednesday raised its flooding protocol alert level for a second time, urging that residents near the burn area voluntarily evacuate or prepare essentials such as medications and important papers. A mandatory evacuation order could come sometime Thursday, officials said.
The city provided thousands of sandbags to residents who streamed into a city yard to fill the bags and drive them away.
‘‘I'd like to stay, but I'm prepared to do whatever the Fire Department asks us to do,'' Mary Waldusky told KABC-TV, as volunteers lined sandbags along her foothill neighborhood. ‘‘We're ready to evacuate with our daughters.''
Sandbags were also being provided in other communities along mountain ranges east and west of Los Angeles, where other fires have burned in recent years, including the area of the May 2013 Springs Fire in the Santa Monica Mountains.
The National Weather Service said light-to-moderate rain from the first storm was expected through midday Thursday.
The weather service said the second storm will be stronger and move across Southern California from late Thursday through late Saturday, reaching Los Angeles County early Friday morning with rainfall amounts ranging from 3-6 inches in the foothills, and up to 8 inches in localized areas.
That second storm will bring by far the heaviest of rain to parched Southern California, Ken Clark, an Accuweather meteorologist, said in an email.
‘‘In fact as much, or more rain, may fall in parts of Southern California than fall, let's say, around the Bay Area when all is said and done,'' Clark wrote.
A wind advisory was scheduled to be in effect until midnight in the San Gabriel mountains and the Antelope Valley. An even more serious high wind watch will be in effect in the Antelope Valley from late Thursday through Friday evening.
State water officials plan Thursday to survey the anemic mountain snow pack, and will likely find that California's precipitation is badly lagging what's needed to quench the region's thirst after 2013 ended as the state's driest year on record.
A so-called Pineapple Express storm brought rain and snow to California earlier this month, and when it departed, the Sierra Nevada snowpack had grown but was still only 29 percent of normal.
Rain fell throughout the day Wednesday in San Francisco, and gave a midday pounding to the Santa Cruz Mountains south of the Bay Area.
The showers caused the cancellation of more than 100 flights at San Francisco International Airport.