Officials say power is slowly returning to Detroit after a "major cable failure" killed the lights in several parts of the city, the AP reports. The outage struck over 900 sites city-wide, the Detroit Free Press reports, shutting down nearly all traffic lights and trapping many people in elevators (firefighters are still performing rescues at downtown elevators as of this writing). Detroit officials say that as of mid-afternoon, about a third of power customers have service restored along with schools, government buildings, and other facilities. Mayor Mike Duggan says the outage is "another reminder of how much work we still have to do to rebuild the city," and notes that Detroit's four-year, $200 million upgrade to its decades-old electrical grid is still underway, the Detroit News reports. (More Detroit stories.)