The Joint U.S.-Canada Power Outage Task Force investigating the Aug. 14, 2003, blackout released a timeline of events Friday, Sept. 12, 2003, that will be instrumental in determining the causes of the widespread outage.

“Dozens of expert investigators from both countries have been working diligently,” U.S. Secretary of Energy Spencer Abraham said. “They have interviewed utility and control-center personnel, examined vast amounts of computer data and sifted through thousands of documents to put this timeline together. But we must now arrange and analyze even larger amounts of additional information to lead us to the specific causes.

“While we are making good progress, this investigation is far from complete. The task force and its working groups and investigation teams have much work ahead of them,” Abraham said.

Herb Dhaliwal, Canada's Minister of Natural Resources and co-chair of the U.S.-Canada Task Force, said, “We have done a preliminary examination of the data. This sequence of events is only a first step in the process of uncovering what happened on Aug. 14. To complete its work, the task force will continue to work with all the parties involved to further analyze the data and come to an understanding of why this has happened.”

The timeline outlines significant physical and electrical events that occurred in a narrow window of time, before and during the cascade that led to the blackout of Aug. 14. This timeline reviews events beginning at approximately noon on that day, to provide a “picture” of the sequence of events and how the grid situation evolved over the afternoon. It focuses chiefly on events that occurred on major transmission facilities (230 kV and greater) and at large power plants. The timeline is available at

Input to the sequence of events came from the North American Electric Reliability Council, independent system operators, utility companies and regulatory agencies from both countries.