An urgent evacuation order was issued for the central California city of Oroville, where authorities warn the auxiliary spillway of a nearby dam appeared to be ready to fail.
In a message posted on Facebook, the California Department of Water resources writes “Officials are anticipating a failure of the Auxiliary Spillway at Oroville Dam within the next 60 minutes.”
A message posted by the Butte County Sheriff states that operation of the spillway had lead to erosion that could lead the spillway structure to fail.
“Failure of the auxiliary spillway structure will result in an uncontrolled release of flood waters from Lake Oroville.”
The warning was later rescinded, as engineers discovered the spillway was eroding slower than they first thought.
The city of 15,000 sits downhill from that lake, and residents were advised to evacuate north to the city of Chico.
Water has since stopped pouring down the auxiliary spillway, and is being ejected once again from the main spillway at a rate of 100,000 cubic feet per second to ‘make room’ for incoming rain storms in the forecast.
Live video from local news helicopters appeared to show water gushing out of the damaged auxiliary spillway, while also beginning to also overflow the emergency spillway and area around it.