Insane drone footage shows massive damage and flooding at California's Oroville Dam

Drone and helicopter footage over Northern California's imperiled Oroville Dam show the widespread damage and furious flooding that forced more than 200,000 people to evacuate on Sunday.

High water levels at Lake Oroville this weekend prompted authorities to use the dam's emergency spillway for the first time in its nearly 50-year history. The main spillway had suffered unexpected erosion earlier this week after heavy rains caused a 30-foot-deep hole in the structure.

In aerial footage, water is seen roaring down the dam's damaged spillway, looking like the world's most terrifying waterslide. The emergency spillway appears more like a muddy mess of small creeks that spill menacingly from the reservoir.

The situation at Oroville Dam comes as much of California is suffering from climate whiplash.

After enduring a record six-year drought, parts of the Golden State are seeing near-record levels of rain and snowfall as a slew of atmospheric "rivers" dump precipitation across the region.

In California's Northern Sierra region, total precipitation is already at 68 inches for the season — far above the 2015-2016 total of 57.9 inches, and only 20.5 inches shy of the record 1982-1983 season, according to the National Weather Service.

With more rain expected later this week, California authorities are scrambling to fix the Oroville Dam's spillways and reduce the reservoir's water levels to avoid another debacle at the dam.

This Tweet is currently unavailable. It might be loading or has been removed.

This Tweet is currently unavailable. It might be loading or has been removed.

The 770-foot-tall Oroville Dam — the nation's tallest — lies 150 miles northeast of San Francisco. Its reservoir is the nation's second-biggest man-made lake.

California's Department of Water Resources on Sunday evening ordered the evacuation of around 200,000 people from towns lying below Lake Oroville.

Officials warned the main and emergency spillways could both fail, sending a dangerous 30-foot wall of water into communities below. California Gov. Jerry Brown issued an emergency order on Sunday to help with response efforts.

By Monday morning, however, the immediate threat seemed to have passed.

Water levels at Lake Oroville had dropped to around 897 feet, below the 901-foot threshold for using the lake's spillways.

Flows over the emergency spillway had stopped, while about 100,000 cubic feet-per-second of water continued down the main spillway, the Department of Water Resources said.

Credit for first video: Instagram/radbones4l via Storyful