Nearly 200,000 Californians living in an area near America's tallest dam were told to flee their homes Sunday after a break at an emergency spillway threatened to inundate the towns below it.
Residents living near the Oroville Dam were warned of an imminent threat that the spillway, which is designed to drain water from Oroville Lake, might fail.
Had the spillway failed, officials feared a 30-foot wall of water could be unleashed into the towns below.
Late Sunday, that threat appeared to lessen. However, officials said many unknowns remain and gave no word as to when the evacuations might be lifted.
Butte County Sheriff Kory Honea said the evacuation would remain in place until more information is analyzed and Gov. Jerry Brown issued an emergency order late Sunday night.
"I've been in close contact with emergency personnel managing the situation in Oroville throughout the weekend and it's clear the circumstances are complex and rapidly changing," Gov. Brown said. "The state is directing all necessary personnel and resources to deal with this very serious situation."
In order to lessen the threat, the California Department of Water Resources said it was releasing 100,000 cubic feet of water per second from the damaged spillway in an attempt to drop the lake depth by 50 feet.
In order to shore up the damage on the spillway, officials reportedly plan to drop rocks or boulders into the damaged area in an attempt to prevent it from degrading further.
Dozens of schools have been closed in the area as residents of Oroville, a town of 16,000 people, were told to head north toward Chico. The towns of Live Oak, Yuba City and Nicolaus, as well as all communities in Feather River Yuba City basin were affected.
The threat comes amid an extremely wet winter for Northern California, where water levels at Lake Oroville rose so high that the emergency spillway was used Saturday for the first time in nearly 50 years.