In February of 2017, The Oroville Dams principle spillway failed.

After the main spillway failed, the operators closed the spillway and let the lake rise for 3 days in order to use the emergency spillway. That spillway also almost failed and they were forced to re open the main spillway and blow out the entire structure into the river which caused the river to dam up and the hyatt power plant started to flood.

They are lucky they didnt lose complete control of the dam.

The dam operators were late to notify emergency services. The sherriff called for a evacuation which lead to a nightmare of 200,000 people scrambling for safety with zero notice.

Final causes of the failure was said to be due to no maintenance and neglect of the entire dam.

This dam has had major problems even from its beginning during construction when the core rotated as they piled up materials.

Its amazing it hasnt failed yet.