For the first time in a decade California's Lake Berryessa has run out of room to hold water.
The Monticello Dam reservoir is full, and it's spilling over into the lake's drain.
Water enters the giant 22-metre wide bellmouth funnel - also known as the 'glory hole' - and exits onto the other side of the dam.
Drone footage shows the result as the water floods over the sides and plummets down the tube.
The New York Times reports water was flowing down the spillway at around 7.5 million litres a minute.