According to NDTV
OROVILLE: Evacuation orders for nearly 200,000 people living below the tallest dam in the United States remained in place early on Monday after residents were abruptly told to flee when a spillway appeared in danger of collapse.
Authorities issued the evacuation order on Sunday, saying that a crumbling emergency spillway on Lake Oroville Dam in north California could give way and unleash 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.
The California Department of Water Resources said on Twitter at about 4:30 pm 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 damaged spillway remained standing.
The state water resources department said crews using helicopters would drop rocks to fill a huge gouge, and authorities were releasing water to lower the lake’s level after weeks of heavy rains in the drought-plagued state.
By 10 pm, state and local officials said the immediate danger had passed with water no longer flowing over the eroded spillway. But they cautioned that the situation remained unpredictable.
“Once you have damage to a structure like that it’s catastrophic,” acting Water Resources director Bill Croyle told reporters. But he stressed “the integrity of the dam is not impacted” by the damaged spillway.