California’s Dam Danger

A mass evacuation follows warnings that the country’s tallest dam could fail

February 13, 2017

An aerial photo shows the damaged Oroville Dam in Oroville, California, on February 11.

Authorities in Northern California ordered nearly 200,000 people to evacuate towns near Lake Oroville on Sunday afternoon. The 770-foot-tall Oroville Dam—the tallest dam in the United States—was reported to be in danger of overflowing, which could spell disaster for residents in the area. Officials warned that if the dam failed, it could send a 30-foot wall of water into the communities below the lake.

The evacuation order came after engineers spotted a hole in the Oroville Dam and told authorities that the dam could fail within the hour.

Lake Oroville, which lies about 150 miles northeast of San Francisco, is one of California's largest man-made lakes. It is a central piece of the state’s government-run water network, supplying water for agriculture in the Central Valley and residents and businesses in Southern California. In recent weeks, the lake has swelled after a series of storms that dumped rain and snow across the state. On Saturday, the lake’s water levels were so high that the Oroville Dam’s emergency spillway was used for the first time since it was built nearly 50 years ago. A spillway is a passage for surplus water to run over or around a dam.

Sounding the Alarm

California Governor Jerry Brown issued an emergency order about the dam. "The state is directing all necessary personnel and resources to deal with this very serious situation,” he said in a statement on Sunday.

Jason Newton, left, of the Department of Water Resources, takes a picture of water going over the emergency spillway on February 11.

Jason Newton, left, of the Department of Water Resources, takes a picture of water going over the emergency spillway on February 11.

The sudden evacuation panicked residents who scrambled to gather their belongings and get to safety. Kaysi and Greg Levias, from Yuba City, packed their car with everything they could fit inside the trunk—mostly clothes and blankets, according to Kaysi.

"We've never been through this before,” she said. “We have two boys and our dog." Everything the family left behind in their apartment was piled as high as possible, in the hope that the items would not get flooded.

As the evacuation continued across the region, many residents grew angry as they sat in bumper-to-bumper traffic for hours.

“You can’t even move,” Raj Gill said. Gill, who manages a Shell gas station, said his boss told him to close the station and flee himself. But he stayed open to feed a steady line of customers. "I'm trying to get out of here too. I'm worried about the flooding. I've seen the pictures—that's a lot of water."

A Red Cross spokesperson said more than 500 people showed up at an evacuation center in Chico, California. The shelter had run out of blankets and cots. A tractor-trailer with 1,000 more cots was stuck in the traffic of those fleeing the potential flooding, said Red Cross shelter manager Pam Deditch.

The threat appeared to ease somewhat on Monday, however. Engineers do not know what caused the cave-in in the Oroville Dam. But Chris Orrock, a spokesman for California’s Department of Water Resources (DWR), said it appears the dam’s main spillway has stopped crumbling even though it is being used for water releases.

Rescue Efforts

Water flows through a damaged spillway in the Oroville Dam in Oroville, California

Water flows through a damaged spillway in the Oroville Dam in Oroville, California

On Sunday, the California National Guard put out a notification to all of its 23,000 soldiers and airmen to be ready to deploy. It is the first time an alert for the entire California National Guard had been issued since 1992. At least 250 state police officers were posted near the dam and along evacuation routes to help people exiting the area. A California Highway Patrol spokesman said two planes would fly Monday to help with traffic control and possible search-and-rescue missions.

By Sunday night, officials announced that water levels in Oroville Lake had decreased and that water was no longer spilling over the damaged area of the dam. But they warned that the threat was not over.

"There is still a lot of unknowns," Butte County Sheriff Kory Honea said. "We need to continue to lower the lake levels and we need to give the Department of Water Resources time to fully evaluate the situation so we can make the decision to whether or not it is safe to repopulate the area."

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