Officials emphasized that although erosion had carved a massive hole in the Oroville Dam's main spillway, the dam itself is structurally sound.
“Believe me, in the last several days there have been a lot of eyes on it,” said Bill Croyle, acting director of the California Department of Water Resources. “Oroville Dam is not in any way a part of the damage that occurred.”
Officials have estimated it could cost $100 million to $200 million to repair the damage to the spillway and other features.
A dramatic scene unfolded on social media Sunday night as the Oroville Dam's emergency spillway was in danger of imminent failure and area residents rushing to evacuate jammed local roads and freeways.
After discovering a hole in Oroville Dam's emergency spillway, officials said late Sunday that they will attempt to plug it using sandbags and rocks. But they stressed the situation remains dangerous and urged thousands of residents downstream to evacuate to higher ground.
Video from television helicopters Sunday evening showed water flowing into a parking lot next to the dam, with large flows going down both the damaged main spillway and the emergency spillway.
They also showed lines of cars getting out of downtown Oroville. An evacuation center was set up at the Silver Dollar Fairgrounds in Chico.