Your trusted source

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, Reuters reports.

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 p.m. PST  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 p.m., 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.

California Governor Jerry Brown asked the Federal Emergency Management Agency on Friday to declare the area a major disaster due to flooding and mudslides brought on by the storms.

The earthfill dam is just upstream and east of Oroville, a city of more than 16,000 people.

At 770 feet (230 meters) high, the structure, built between 1962 and 1968, is the tallest U.S. dam, exceeding the Hoover Dam by more than 40 feet (12 meters).