Evacuations expanded over likely failure of Oroville Dam spillway

Evacuations orders were expanded 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 Butte County Sheriff’s Department issued the evacuation order at about 4:20 p.m. after the hazardous situation developed. Authorities are concerned the erosion could lead to the failure of the Oroville Dam’s emergency spillway.

Failure of the auxiliary spillway structure will result in an uncontrolled release of flood waters from Lake Oroville.

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.

Butte County Sheriff Kory L. Honea said the evacuation order went out after engineers spotted a hole that was eroding back toward the top of the spillway.

“I couldn’t risk the lives of thousands of people, so we took this significant step.” said Honea during the early evening press conference.

Honea said that the crews with the California Department of Water Resources were doing everything they could to avert the crisis.

“I would rather be safe than sorry. I would rather have people moving out of the area, hopefully to safety, than to sit and hope for a solution,” said Honea.

Experts told Honea that the erosion was not advancing as rapidly as had been initially thought, giving hope that the emergency spillway might not actually fail.

Honea said two inches of water is still coming over the dam, but that is significantly down from earlier flows.

Honea says there is a plan to plug the hole by using helicopters to drop rocks into the crevasse.

The California Department of Water Resources also issued it’s own statement early Sunday evening.

“The concern is that erosion at the head of the auxiliary spillway threatens to undermine the concrete weir and allow large, uncontrolled releases of water from Lake Oroville,” the statement read. “Those potential flows could exceed the capacity of downstream channels.”

Residents of Oroville were advised to evacuate in a northward direction such as towards Chico, officials said. Other cities were advised to follow the orders of their local law enforcement.

There is a 3-mile backup on the highway leaving Oroville as residents rushed to higher ground .

The Governor’s Office of Emergency Services activated all State sponsored California Swift Water Rescue Teams as part of the evolving Dam Emergency.

Department of Water Resources spokesman Kevin Dossey tells the Sacramento Bee the emergency spillway was rated to handle 250,000 cubic feet per second, but it began to show weakness Sunday at a small fraction of that.

Flows through the spillway peaked at 12,600 cubic feet per second at 1 a.m. Sunday and were down to 8,000 cubic feet per second by midday.

An evacuation center has been set up at the Silver Dollar Fairgrounds in Chico. Shelter for large animals is being provided at Camelot Equestrian Park on 1985 Clark Road in Oroville.

For evacuation info, Butte County residents can dial 2-1-1 from landline or cell phones. Yuba or Sutter residents can call 1-866-916-3566.