As Hole in Oroville Dam Spillway Widens, Officials Consider Opening Emergency Spillway

Pam Wright
Published: February 10, 2017

Officials might be forced to open an emergency spillway in northern California after heavy rains and rapid snowmelt opened a gaping hole in the main spillway of the tallest dam in the United States.

Butte County Sheriff’s officials, in conjunction with CAL FIRE/Butte County Fire, California Office of Emergency Services and Oroville City officials announced Thursday night that the Oroville Dam emergency spillway may be in use as early as Friday evening.

The initial cave-in of the spillway occurred Wednesday when chunks of concrete went flying from the water surging down the spillway, creating a 200-foot-long, 30-foot-deep hole. The hole is continuing to grow.

"I've never seen it like this, ever," Charles Wing told the Los Angeles Times. "And I've been here 44 years."

Engineers are uncertain how the cave-in occurred. 

Officials reassured the public, saying there was no immediate danger to homes, but residents in communities along the Feather River were urged to prepare in the event an evacuation warning is issued. 

(MORE: 2 Dead in California, Nevada Flooding and Mudslides)

California's Department of Water Resources spokesman Eric See said the massive gap in the spillway is expected to keep growing until it reaches bedrock.

The department had little choice on Thursday but to again ramp up the outflow from Lake Oroville over the damaged spillway to try to keep up with the torrential rainfall flowing into Oroville Lake from the Sierra foothills.

According to the Department of Water Resources website, the reservoir was 96 percent full as of Thursday, with water 7 feet from the top of the emergency spillway

MORE: Flooding in Nevada, California — February 2017

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