New York City Goes Dark

On the afternoon of August 14, 2003, a power plant outside Cleveland tripped offline just as a summer heat wave pushed electricity demand to its limits. A software bug in the alarm system at FirstEnergy, the Ohio utility running that stretch of grid, meant operators never got the warning as overloaded transmission lines sagged into trees and failed one after another. The cascade raced east in minutes, and by just after 4:10 p.m. it reached New York, cutting power to the entire city along with much of the Northeast and Ontario. Subways stopped mid tunnel, all 11,600 traffic signals across the five boroughs went black at once, and hundreds of thousands of commuters had to walk home or across the bridges with no trains, no cabs, and barely any cell service. It took until Friday night, nearly 29 hours later, for the last lights in the city to come back on.