Northeast blackout of 2003


This image shows states and provinces that
experienced power outages. Not all areas
within these political boundaries were affected.

Date: August 14–16, 2003
Duration: 2 hours–4 days, depending on location
Location: Northeastern United States, Southeastern Canada
Type: Blackout
Cause Failure of alarm system in FirstEnergy control room leading to cascading loss of transmission and generation capability.
Outcome: 55 million people affected
Deaths: Almost 100

The Northeast blackout of 2003 was a widespread power outage throughout parts of the Northeastern and Midwestern United States, and most parts of the Canadian province of Ontario on Thursday, August 14, 2003, beginning just after 4:10 p.m. EDT.

Most places restored power by midnight (within 7 hours), some as early as 6 p.m. on August 14 (within 2 hours), while the New York City Subway resumed limited services around 8 p.m. Full power was restored to New York City and parts of Toronto on August 16. At the time, it was the world's second most widespread blackout in history, after the 1999 Southern Brazil blackout. The outage, which was much more widespread than the Northeast blackout of 1965, affected an estimated 55 million people, including 10 million people in southern and central Ontario and 45 million people in eight U.S. states.

The blackout's proximate cause was a software bug in the alarm system at the control room of FirstEnergy, which rendered operators unaware of the need to redistribute load after overloaded transmission lines drooped into foliage. What should have been a manageable local blackout cascaded into the collapse of much of the Northeast regional electricity distribution system.

{snip}