LOS ANGELES (AP) — The second of back-to-back atmospheric rivers churned through California, flooding roads, knocking out power to hundreds of thousands and leading forecasters to warn of possible hurricane-force winds and mudslides. The slow-moving storm is expected to dump heavy rain on Southern California on Monday, and officials there warned of potentially devastating flooding. Evacuations have been ordered for canyons that burned in recent wildfires that are at high risk for debris flows. The system knocked down trees and power lines Sunday in the San Francisco Bay Area, where winds topped 60 mph in some areas. Gusts exceeding 80 mph have been recorded in the mountains.