Once the Lake Oroville Spillway was damaged due to erosion and a collapse the Department of Water Resources (DWR) greatly reduced the flow of water leaving the Oroville Dam. With rain and runoff entering Lake Oroville, more water was entering than leaving. The emergency spillway would need to be used for the first time in the history of the dam. Minor flooding in Oroville had started. On February 12, 2017 at around 6 PM the DWR anticipated a catastrophic failure of the emergency spillway, sending more water down stream. Many cities in Butte and Sutter counties were evacuated.