Residents below the tallest dam in the United States, near Oroville in Northern California, were urgently ordered to evacuate on Sunday after a spillway appeared for a time to be in danger of imminent collapse.
The abrupt evacuation orders came as authorities said that an auxiliary spillway on the Lake Oroville Dam could give way at any time, unleashing floodwaters onto rural communities along the Feather River.
"Immediate evacuation from the low levels of Oroville and areas downstream is ordered," the Butte County sheriff said in a statement posted on social media. "This is NOT A Drill." The California Department of Water Resources said on Twitter at about 4:30 p.m. PST (0030 GMT Monday) that the spillway next to the dam was "predicted to fail within the next hour." Several hours later the situation appeared less dire as the spillway remained standing and the Water Resources department said crews using helicopters would drop rocks to fill a gouge in the spillway. Authorities were also releasing water to lower the lake's level after weeks of heavy rains in the drought-plagued state.