Over 180,000 residents were ordered to evacuate the area due to the possibility of failure of the alternate spillway at Oroville Dam. Butte County Sheriff Kory Honea said during a news conference Sunday night that he had no choice but to order the evacuation.
You can watch the situation in the area on the livestream below:
Thousands clogged highways leading out of the area headed south, north and west and arteries major and minor remained jammed as midnight approached on the West Coast, according to National Post.
Even as they fled, however, the flow of water over the spillway halted late in the evening, stabilizing the crisis. But officials warned the damaged infrastructure could create further dangers as storms approach in the week ahead and it remained unclear when residents might be able to return to their homes.
Lake Oroville is one of California’s largest man-made lakes with 3.5 million acre-feet of water and 167 miles of shoreline, and the 770-foot-tall Oroville Dam is the nation’s tallest, about 44 feet higher than Hoover Dam on the Colorado River. The lake is the linchpin of California’s government-run water delivery system, sending water from the Sierra Nevada for agriculture in the Central Valley and for residents and businesses in Southern California.
After a record-setting drought, California has been battered by potentially record-setting rain, with the Northern California region getting 228 per cent more than its normal rainfall for this time of year. The average annual rainfall of about 50 inches had already been overtaken with 68 inches in 2017 alone.
There was never any danger of the dam collapsing. The problem was with the spillways, which are safety valves designed to release water in a controlled fashion, preventing water from topping over the wall of the colossal dam that retains Lake Oroville.
Earlier this week, unexpected erosion crumbled through the main spillway, sending chunks of concrete flying and creating a large hole. Then sheets of water began spilling over the dam’s emergency spillway for the first time in its 50-year history.
Water from rain and snow rapidly flowed into the lake, causing it to rise to perilous levels, and sending water down the wooded hillside’s emergency spillway, carrying murky debris into the Feather River below.
“Once we have damage to a structure like that, it’s catastrophic,” Bill Croyle, acting director of the state’s Department of Water Resources, said in a 10 p.m. news conference Sunday. “We determined we could not fix the hole. You don’t just throw a little bit of rock in it.”
Anticipating a possible catastrophe for the Lake Oroville area, located about 75 miles north of Sacramento and about 25 miles southeast of Chico, the Butte County Sheriff’s Office ordered evacuations, adding in a news release that this was “NOT a drill.”
But as the reservoir’s water levels lowered, the flows over the emergency spillway ceased.
California Democratic Gov. Jerry Brown issued an emergency order to boost the state’s response to the evacuation efforts and spillway crisis, which Brown called “complex and rapidly changing.” Despite the minimized threats, Butte County Sheriff Kory Honea said in a news conference at about 10 p.m. local time Sunday that he would not be lifting the mandatory evacuation order until water resources officials had a better grasp on the anticipated risks.
Facilities for sheltering people, churches, schools, and seven Sikh temples opened their doors in a striking display of common purpose and community. People offered to open their homes to strangers via Twitter messages. Hotels and motels out-of-harm’s-way filled up quickly, creating little communities of the suddenly displaced. The dam itself remained structurally sound through the evening, the state Department of Water Resources (DWR) said.
In a news conference Sunday night, Honea said helicopters would be deployed to drop bags of rocks into the crevice and prevent any further erosion.
Officials doubled the flow of water out of the nearly mile-long primary spillway to 100,000 cubic feet per second, helping to reduce the lake’s levels. The normal flow is about half as much, but increased flows are common at this time of year, during peak rain season, officials said.
Croyle said that the lake would need to lower almost 50 feet to reach levels at which the system would normally operate. Croyle said that personnel were unable to access the eroded emergency spillway Sunday to do repair work. Officials aimed to continue to discharge as much water as possible ahead of upcoming storms, without adding too much pressure to the already damaged infrastructure.
“Our goal is to be able to use that infrastructure throughout this wet season,” Croyle said. Forecasts indicate that dry weather will dominate through Tuesday, but a series of Pacific storms are expected to arrive across the region Wednesday into Thursday, bringing up to 4 inches of rain to parts of the Central Valley, according to the National Weather Service.
Honea called the evacuation order a “critical and difficult decision” and said he recognized it would cause significant dislocations and traffic jams, which it did. Residents of Oroville, a town of 16,000 people, were ordered to head north toward Chico, while other nearby residents drove south toward Sacramento.
“I recognize how tough this situation is on people,” Honea said in the 10 p.m. news conference. “I recognize that we’ve had to displace a lot of people.”
The California National Guard will provide eight helicopters to assist with emergency spillway repair, Adjutant General David S. Baldwin said in a news conference. All 23,000 soldiers and airmen statewide received an alert to be “ready to go if needed,” Baldwin said. The last time such an alert was sent out to the entire California National Guard was the 1992 Los Angeles riots, which erupted after a trial jury acquitted four officers of the Los Angeles Police Department of the use of excessive force in the videotaped arrest and beating of Rodney King.
Officials said 250 law enforcement personnel were being deployed to patrol the evacuated areas.
Travelers reported traffic at a standstill on some routes, especially on Highway 99 between Oroville and Chico.