What began as a damaged power line and a software malfunction in Ohio led to overloaded equipment throughout the interconnected power system stretching from Canada into the northeast United States. The power surge from Ohio triggered safety systems across the region, creating what is thought to have been the most widespread outage in both United States and Canadian history and the second-most-widespread in the world. It took around two days for all overloaded components to be checked and brought back online, with some smaller areas remaining without power for nearly a week.

In New York, the city and most of the state were in the dark. Traffic lights were out and elevators and the subway were stopped, leaving many commuters in need of emergency evacuation and with no way to reach their homes as night began to fall. Some stayed in office buildings, on the floors of generous co-workers who lived nearby, or even slept outside, while others attempted to walk home or catch a ride on a bus or taxi, turning Manhattan's bridges into one-way exits.