An aerial image of the spillway with heavy overspill from the dam.  Embedded is an artists rendering of the Oroville dam structure indicating damage to the concrete spillway.

Oroville Spillway Situation Feb 2017

More than 180,000 people are under evacuation orders which also includes “all Yuba County on the valley floor” and the city of Marysville. Evacuations have been ordered for low levels of Oroville, California, and several areas downstream from Lake Oroville because of erosion on the Oroville Dam’s auxiliary spillway, according to the Butte County Sheriff’s Office.

Background

More than 180,000 people are under evacuation orders which also includes "all Yuba County on the valley floor" and the city of Marysville. Evacuations have been ordered for low levels of Oroville, California, and several areas downstream from Lake Oroville because of erosion on the Oroville Dam's auxiliary spillway, according to the Butte County Sheriff's Office. Source

Oroville Dam is an earthfill embankment dam on the Feather River east of the city of Oroville, California in the United States. At 770 feet (230 m) high, it is the tallest dam in the U.S.[7] and serves mainly for water supply, hydroelectricity generation and flood control. The dam impounds Lake Oroville, the second largest man-made lake in the state of California, capable of storing more than 3.5 million acre-feet (4.4 km3),[8] and is located in the Sierra Nevada foothills east of the Sacramento Valley. Via Wikipedia

Earlier this week, chunks of concrete flew off the nearly mile-long spillway, creating a 200-foot-long, 30-foot-deep hole. Engineers don't know what caused the cave-in that is expected to keep growing until it reaches bedrock. source

Significant Updates (most recent first)

Feb 13:

  • ACSO accepted 470 inmates from @ButteSheriff. Inmates are safe at Santa Rita Jail. We don't anticipate them being here long. source
  • 6:31 PM CAL FIRE update: The Department of Water Resources advises that the primary spillway continues to flow at 100,000 cfs and lake levels have dropped to 894’ feet. After evaluating the erosion on the emergency spillway, a plan was put in place to prevent further erosion. Utilizing trucks and helicopters, crews moved large rocks and gravel to fill erosion on the emergency spillway. DWR staff continues to inspect and evaluate the emergency and primary spillways for further erosion. All California Department of Fish and Wildlife areas and facilities, except for the Chico field office, are closed. The wildlife areas are flooded and extremely dangerous, please do not attempt to visit them. source
  • 6:20 PM Nevada County will proclaim a local emergency tomorrow. Why? On February 12, 2017 at approximately 4 p.m., Nevada County began providing emergency services and opened its emergency shelters to provide food, emergency supplies, medical attention, shelter, transportation and services for the elderly, social services, therapists, animal food and shelter, and to provide supplies and other services as needed to address the complex and rapidly changing circumstances to individuals displaced by the emergency evacuation. Nevada County is currently housing and providing food and resources to approximately 800 evacuees, 80 Yuba County Jail inmates, and 30 Juvenile Hall juveniles, as well as housing Yuba County’s temporary Emergency Operations Center, and it is anticipated that this emergency will exist for the next several days, and until the Oroville Dam Spillway emergency and threat of uncontrolled flooding has stabilized. source
  • 5:54 PM California Attorney General Xavier Becerra today issued a consumer alert concerning price gouging in the wake of the Oroville Dam Auxiliary Spillway Incident and related evacuations.
  • 4:58 PM Nevada County is adding an emergency item to tomorrow’s BOS agenda. A proclamation of a local emergency due to extreme precipitation, excessive water capture and significant damage to the Oroville Dam spillways and requesting the governor proclaim a state of emergency for Nevada County. source
  • 4:13 PM DWR: Efforts are underway to make repairs to both the primary and auxiliary spillways at Lake Oroville. source 4:05 PM Helicopters have started to drop boulders at the emergency spillway. source
  • 3:56 PM FEMA Activates To Support California with Potential Oroville Auxiliary Spillway Failure FEMA logistics will supply 150,000 one-litre bottles of water; 20,000 blankets; and 10,000 cots to the state today. FEMA’s Liaison Officers continue to work with the California Office of Emergency Services Operations Center and the California Department of Water Resources State-Federal Flood Operations Center. FEMA encourages those in the areas affected, or potentially affected by the severe weather to monitor local radio, TV stations or official social media accounts for updated emergency information, and to follow the instructions of state, tribal and local officials. source
  • 2:18 PM All jurisdictions within Yuba and Sutter Counties remain under an evacuation notice. Local officials are monitoring the situation and will provide updates on a regular basis. source
  • Oroville - Gas station by Feather Falls Casino is down to Premium gas only and running low source
  • The California National Guard is transporting blankets and cots to temporary shelters for evacuated residents. Source They are also prepared to provide medical support and evacuation if needed. source
  • 12:22 PM All evacuation orders remain in place, says Butte County Sheriff. source
  • 12:19 PM DWR: Releasing over 110,000 CFS via the main Oroville Spillway. Lake level dropping around 8′ per day. No water has flown over the emergency spillway at this time. source
  • Yuba Jail inmates were evacuated safely. A list will follow on the County website. Source
  • 10:01 AM Yuba County update: This morning, ALL Yuba County communities on the valley floor are still under Mandatory Evacuation, with the exception of Wheatland, which is under Voluntary Evacuation. The Mandatory Evacuation applies to District 10, Marysville, Linda, Olivehurt, Arboga, and Plumas Lake. Please DO NOT return to those areas until we determine it is safe to do so. We are working to keep people out of harm’s way. We understand evacuation orders in Sutter County, Yuba City and Live Oak are also unchanged. source
  • 8:53 AM Efforts are being undertaken to make repairs to both, the primary and emergency spillways. source
  • 8:35 AM DWR engineers and soil technicians are assessing the auxiliary spillway damage now. Updated conditions will be posted as soon as available. source
  • 7:20 AM At 7:00 am Lake Oroville reservoir elevation is 897.55 ft. Reported outflow is 99,804 cfs. source
  • WHEATLAND ONLY -- Changed to a Voluntary Evacuation. All other communities still mandatory. source
  • As of Monday at 5:00am local time, approximately 188,000 people are under evacuation orders and evacuations remain in progress. Humanity Road continues to amplify officials and monitor for urgent needs. Potential anticipated urgent needs are stranded motorists, gas station shortages, shelter supplies needed, and identifying misinformation and rumors. Additional rain is forecasted for the already heavily soaked area. Sacramento County which is south of the impact area and suffering under flooding conditions is also an area of concern. Humanity Road began monitoring the Oroville Dam on Friday Feb 10th when the primary spillway was compromised. Helpful official agency social media links were collected in advance of evacuation and guidance from officials and which officials to follow amplified in social media. On Sunday Feb 12, the emergency spillway became compromised and evacuations were ordered for parts of three counties.
  • Due to the heightened risk to downstream communities, and at the request of a California county emergency management agency, the Humanity Road disaster desk was elevated to status Red and a special report was published to our activation partner, as well as our situation report.

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