Northeast Blackout

Millions of people were left without power on August 14, 2003 at 4:09 PM when the largest blackout in the history of North America occurred.  The blackout began when three transmission lines failed near Cleveland, Ohio.  Within minutues, over 100 power plants in the United States and Canada were overwhelmed and knocked offline.

The blackout affected several major metropolitan areas — including Detroit, Cleveland, Columbus, New York, Toronto, and Ottawa.  This composite hydrograph displays normal dry weather conditions from a flow monitoring located in Oakland County, Michigan during this period.  Flow monitoring data from August 14th are shown for comparison.

Note the dramatic drop in flow after the power failure.  The minimum flow during the blackout was well below the normal night-time flow.  This example illustrates how the disruption of one basic service can affect the use of another.


  • Gibbs, N. (2003).  ‘Lights Out,’ Time, Volume 162, Issue 8, 30-39.


Special thanks are extended to the Oakland County Drain Commissioner for contributing this flow monitoring data and authorizing its use for this purpose.