The L.A. Times reports:
Residents of Oroville and nearby towns were ordered to immediately evacuate on Sunday afternoon after a hole was discovered at the emergency spillway for the Oroville Dam.
Officials said late Sunday they will attempt to plug the hole using sandbags and rocks but stressed the situation remains dangerous and urged thousands of residents downstream to evacuate to higher ground.
The National Weather Service said the auxiliary spillway at the Oroville Dam was expected to fail about 5:45 p.m., which could send an “uncontrolled release of flood waters from Lake Oroville.”
Just yesterday the public was told there was no danger. Now there are mandatory evacuations underway, traffic snarls, and a lot of confusion. Some reports state that the dam is danger of failing, while other reports (which appear to be more accurate) say that the emergency spillway is in danger, not the dam itself.
If the dam itself were to break, it would be catastrophic. The Sacramento Bee reports: Marysville, Yuba County evacuated as Oroville spillway collapse feared. Under a section titled Worst Case Scenario the paper says:
There is no map showing exactly what will happen if the emergency spillway collapses tonight. Officials only have a map showing a failure of the dam. That worst case scenario is useful in that it shows where water goes and how fast it gets there.
Water would get to the town of Oroville within an hour.
If Oroville Dam were to suffer a massive breach, water would get to the town of Oroville within an hour, according to GIS maps maintained by CalFire.
Within two hours, the small town of Briggs would be affected. In three hours, Gridley would be hit. Water would reach Live Oak in five hours..
It would take eight to 12 hours for the water to get to Marysville and Yuba City.
If the dam completely failed, flood depths could reach more than 100 feet in Oroville and up to 10 feet in Yuba City.
There’s some dramatic video here, but the statement in the tweet that the dam is expected to fail appears to be wrong:
— ABC News (@ABC) February 13, 2017