A towering spillway at the nation's tallest dam was crumbling, and tens of thousands of people were fleeing for their lives. But as darkness fell, state officials realized dealing with the unfolding crisis in Northern California was about to get even worse: They couldn't see.
For years, federal regulators urged state officials in charge of the Oroville Dam to consider installing cameras, lights and more sensors and monitors to help alert managers to potential structural problems and, in a crisis, ensure there would be time to evacuate towns downstream. But on Feb. 12, as murky floodwaters washed away the second of two failing spillways, nightfall left officials struggling to figure out what was happening.
"Can't confirm. Dark," wrote a state water agency engineer, who was serving as note-taker during an emergency meeting of top officials in the first hours after an evacuation order.
"Don't have eyes. Until we see it, assume it is a threat," said another unidentified official at the meeting, according to the 35 pages of handwritten and typed notes obtained by The Associated Press in response to a public records request. It was one of a series of calls and meetings that at various times included Gov. Jerry Brown, his Cabinet secretary and others struggling to assess the risk from the badly eroding emergency spillway.
The documents reveal for the first time the difficulty Oroville's managers had gauging the evolving dangers for 188,000 people who were ordered to evacuate below the huge dam: State water officials used drones and scrambled to borrow cameras and helicopter rides from other agencies to inspect their own dam and its spillways.
At least since 2011, the Federal Energy Regulatory Commission, which oversees hydropower dams, had expressed concern that Oroville Dam and adjoining structures along Northern California's Feather River needed cameras and other monitors to spot dangerous structural failures, according to documents obtained by AP.
In 2011, federal regulators noted communities immediately downstream likely would not have time to evacuate if the dam abruptly failed. They urged California's Department of Water Resources to install more technology to detect signs of sudden structural breakdowns, including remote cameras, nighttime lighting and reservoir elevation sensors.
During the February crisis, water managers borrowed a camera from the state Transportation Department to provide a live video feed, and tried to find out during the first hours after the evacuation if that camera operated in the dark so they could see the disintegrating emergency spillway.
They borrowed 10 cameras in all, training most on the other, main spillway. They pointed one toward the emergency spillway, but it was too far away to capture the portion that was falling apart.
"Even with all of this technology in place, continuous monitoring at night was difficult as the drones were not equipped with infrared cameras and the helicopters are limited on the number of hours they can be in the air," water agency spokeswoman Erin Mellon said in an email.
The federal energy commission, which is investigating the near-catastrophe, will probe the issue of cameras and other structural monitors, spokeswoman Celeste Miller told AP.
The state water agency, which oversees the dam, rejected installing cameras, deeming them impractical because of the size of the dam complex, which includes 6 miles (10 kilometers) of embankment and the 770-foot-tall (235-meter) dam, Mellon, the agency spokeswoman, said.
Water agency officials told federal regulators they would use roving patrols instead, although regulators noted it could take patrols 20 minutes or more to reach and verify a trouble spot. The agency also later installed sensors to detect if water started dropping in California's second-largest reservoir, signaling a breach.