State officials are waiting for the light of dawn to inspect an erosion scar on the potentially hazardous emergency spillway at northern California’s Oroville Dam, the tallest and largest dam in the United States.
California Department of Water Resources Action Director Bill Croyle says officials in helicopters overflew the spillway Sunday night to visually inspect it. The dam is located is located in the foothills of the Sierra Nevada mountains northeast of the Sacramento Valley. Heavy rain and snowfall this season prompted the overflow.
Evacuations for at least 188,000 people living below the dam were ordered Sunday after officials warned the emergency spillway was in danger of failing and unleashing uncontrolled flood waters on towns below.
Water levels at the huge dam are continuing to drop and stopping water from spilling over the emergency spillway.
California Department of Water Resources officials say flows into the lake are just under 45,000 cubic feet per second. Outflows remain high at nearly 100,000 cubic feet per second.
“Immediate evacuation from the low levels of Oroville and areas downstream is ordered,” the Butte County Sheriff’s Office wrote on Facebook last night.
“Operation of the auxiliary spillway [led] to severe erosion that could lead to a failure of the structure. Failure of the auxiliary spillway structure will result in an uncontrolled release of flood waters from Lake Oroville,” the sheriff’s office said.
