An unusually strong storm system called an atmospheric river was dousing Southern California on Friday and was expected to continue dumping heavy rain over the region for days as forecasters warned of rockslides and debris flows especially in the Los Angeles areas that were ravaged by wildfires earlier this year.

An " unusually strong storm system " is raising concerns about flooding in much of Southern California on Saturday, according to the National Weather Service.

More than four inches of rain fell over coastal Santa Barbara County early Friday as the storm moved south toward Los Angeles, according to the National Weather Service.