The Oroville Dam is the US’s tallest dam with a total height of 235 meters. It is located 150 miles northeast of San Francisco, forming Lake Oroville one of California’s largest man-made lakes. Now it becomes famous for another reason: 188.000 people have been evacuated after Northern California authorities warned an emergency spillway.
The evacuation was ordered Sunday afternoon after engineers spotted erosion on the dam’s secondary spillway. Officials warned residents that the spillway could fail within an hour.
The dam was in danger of failing Sunday and unleashing uncontrolled flood waters on towns below.
The cities of Oroville, Gridley, Live Oak, Marysville, Wheat land, Yuba City, Plumas Lake, and Olivehurst were all under evacuation orders.
According to officials the Oroville Lake levels had decreased by Sunday night as authorities had let water flow from its main spillway. Butte County Sheriff Kory Honea said engineers with the Department of Water Resources informed him shortly after 6 p.m. that the erosion on the emergency spillway at the Oroville Dam was not advancing as fast as they thought.
The California Department of Water Resources said it is releasing as much as 100,000 cubic feet per second from the main, heavily damaged spillway to try to drain the lake.