Washington: At least 130,000 people were asked to evacuate in the area near the Oroville Dam in California, US, Sunday after authorities warned an emergency spillway in the structure was in danger of failing and unleashing uncontrolled flood waters on towns below.
The Butte County Sheriff's Department issued the evacuation order at about 4:20 p.m. after the dangerous situation developed. Authorities are concerned the erosion could lead to the failure of the Oroville Dam's emergency spillway.
Evacuations orders were expanded later Sunday evening for areas of Butte and Yuba counties downstream from the Oroville Dam after one of the dam's emergency spillway was on the verge of collapse because of severe erosion, according to authorities.
The erosion at the head of the emergency spillway threatens to undermine the concrete weir and allow large, uncontrolled releases of water from Lake Oroville, the California Department of Water Resources said. Those potential flows could overwhelm the capacity of downstream channels and levees.
The good news being reported late Sunday night was that the release of water from the main spillway had stopped water from going over the damaged auxiliary spillway.
According to the Butte County officials, in addition to downtown Oroville and Thermalito, other evacuated areas include the towns of Gridley, Biggs and Loma Rica as well as areas along the Feather River south of Butte County.
Additionally, there were evacuations ordered in Yuba County including the areas around Hallwood, Marysville, Olivehurst/Linda and Plumas Lake.