A single photograph of rapid erosion below Oroville Dam's emergency spillway -- and an unidentified geologist's worried question about whether the local sheriff knew how dire the situation might be -- were the key events that led to the evacuation of 180,000 people living along the Feather River on Feb. 12.
As people fled Oroville and surrounding communities, Butte County Sheriff Kory Honea, who ordered the evacuation, described the situation as "just an ugly, shitty mess, and we are trying to make the best of it."
Those details of the Oroville crisis emerge from a series of stories and interviews published by The Associated Press, the Sacramento Bee and the Chico Enterprise-Record. The accounts are based on 35 pages of notes from the California Department of Water Resources that AP obtained under the California Public Records Act.
The notes recount how during the afternoon of Feb. 12, five days after a breach in the dam's main spillway triggered a series of events that led to an uncontrolled overflow over an emergency weir. The overflow, the first in the dam's 48-year history, rapidly eroded a slope below the weir -- a scenario that a 2014 safety review had deemed so unlikely it didn't merit serious study.
As late as 2 p.m. on Feb. 12, the Department of Water Resources was reassuring the public that the flows, which were just a tiny fraction of those envisioned pouring over the weir and down a steep slope to the Feather River, were under control.