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


The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.

Ad Blocker Enabled

Featured Blogs

More Record Heat Invading the U.S. as Cleanup From Rare February Tornadoes Begins

By Dr. Jeff Masters
February 27, 2017

Record warmth slathered the Northeast on Friday and Saturday, the latest chapter in a phenomenal sequence of unseasonal mildness during the last half of February. As of Monday morning, NOAA’s U.S. Records site had catalogued 5857 daily record highs for the month, with only 95 daily record lows.

California Precipitation: From Famine to Feast

By Christopher C. Burt
February 25, 2017

It’s amazing what a difference one year can make. California’s five-year long drought has come to a dramatic halt (or at least interruption) this winter season. The latest California Drought Monitor report, released on February 23rd, has no portion of the state under ‘Extreme Drought’ conditions for the first time in four years. Last year on this date 61% of state was enduring such.

An extraordinary meteorological event; was one of its results a 1000-year flood?

By Stu Ostro
October 5, 2015

The confluence of meteorological ingredients the first weekend in October 2015 resulted in an extraordinary weather event with severe impacts. Was one of them a 1000-year flood?

Why the Arrest of a Science-Loving 14-year-old Matters

By Shaun Tanner
September 16, 2015

By now, many of you have heard or read about the arrest of Ahmed Mohamed, a 14-year-old high school student from Irving, Texas. Ahmed was arrested because school officials called the police after he showed one of his teachers his homemade clock. Mistaken for a bomb, Ahmed was taken into custody, interrogated, shamed, suspended (still on suspension today, Wednesday), and reprimanded. All of this after it has been found that the "device" he brought to school was indeed, a homemade clock.