The rain has started to return in Northern California and will continue over the next few days, but officials aren't as concerned about the upcoming weather so much as the damage already done to the Oroville Dam's already compromised main spillway.

The risk of flooding has dropped substantially, but Butte County Sheriff Kory Honea warned residents Wednesday that they remain in "an emergency situation."

How the Oroville Dam situation became a crisis

Here are some key facts about the Oroville Dam emergency:

  • The mass evacuations underway below the Oroville Dam capped a week of frantic efforts to prevent flooding as the reservoir behind America’s tallest dam reached capacity and its main spillway was severely damaged.
  • On Saturday, water levels rose so high that an emergency spillway was used for the first time. Officials initially believed the measure worked. But on Sunday afternoon, as more water from record storms flowed into Lake Oroville, officials detected a hole in the emergency spillway. That prompted the evacuation order.
  • Officials are trying to reduce water levels at the dam and repair the emergency spillway.
  • Officials worry that a failure of the emergency spillway could cause huge amounts of water to flow into the Feather River, which runs through downtown Oroville, and other waterways. The result could be flooding and levee failures for miles south of the dam, depending on how much water is released.
  • Officials have said they don’t know how much water would run into the Feather River. But a huge release could flood many communities. Right now, river levels are still below flood stage.

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