Before-and-after footage shows how an atmospheric river transformed the Los Angeles River, sending water surging through the channel after torrential rain soaked Southern California. | AccuWeather

Live: Los Angeles River channel camera

Credit: Here's a look at the Los Angeles River channel outside our studios in Universal City. http://4.nbcla.com/MKhgrNQ | NBC LA

Residents in a section of Wrightwood were evacuated Wednesday due to heavy flooding and debris flow, fire officials said. | FOX 11 Los Angeles