On Sunday, nearly 200,000 people received notice to evacuate their homes immediately, as the nearby Oroville Dam appeared to have been structurally compromised by sudden erosion. An imminent failure of the dam’s auxiliary spillway was anticipated, and though the spillway has held, expected storms this coming week make the future of the area uncertain.
The Washington Post reports that the dam itself is structurally sound, but a hole in the main spillway is still threatening the area. Spillways are meant to lower water levels and release pressure on the dam in a controlled manner. California has been experiencing a record-setting drought for years, but so far in 2017 the rainfall has been at 228 percent above normal for the area. This is the first time in 50 years that water has come down the emergency spillway.