The Biggest Power Outages in US History

USA’s electric grid is made up of an astounding 450,000 miles of high voltage transmission lines. These power grids supply over electricity to over 140 million customers over residences, industries, and businesses. Power outages and blackouts can occur anytime. People use electricity every day and take it for granted that electricity will be readily available all the time. This isn’t the case all the time – for various reasons. Typically, power outages and blackouts are easily manageable and can be resolved within a matter of minutes or in an hour.

However, there have been instances where this wasn’t possible. In some situations, people had a power outage for many days. Businesses and industries were greatly affected along with transportation and communication.

Here are the biggest power outages in US history:

New York City (1977)

This major blackout was caused by a lightning strike on the substation by the Hudson River. That lightning tripped two circuit breakers that were used to divert the power and protect the circuit. A combination of loose locking nuts and slow upgrade cycle stopped the breakers from closing and allowing the power to flow again.

A second and third lightning strike followed and it caused even more problems. After over an hour, New York’s largest power generator went down.

Northeast Blackout (1965)

On November 9th, 1965, there was a major disruption in Northeast’s power supply and it left only 30 million people without any power. This blackout lasted for over 13 hours and affected a lot of areas in the Northeastern United States.

This blackout occurred because one of the maintenance workers didn’t set the protective relays high enough. A tiny surge in power tripped the relay and this deactivated the major power line.

West Coast Blackout (1982)

This major blackout took place on December 22nd, 1982 and was caused by the high winds along the coasts of the Western United States. High winds knocked down the key transmission tower into a line tower which caused 3 other towers to fail. Even more problems occurred when communication issues arose and it prevented instructions from being passed along. Even the backup plans failed because the equipment wasn’t configured to handle such a mammoth failure.

Western North America Blackout (1996)

This blackout refers to two blackouts which occurred 6 weeks apart in the same area. It is believed that both of these power outages took place because of the high demand for power during July and August, two incredibly hot months of 1996.

These outages were caused in Idaho, Utah, California and other nearby places because there wasn’t enough electricity. This caused voltage instability and the grid failed. Over 2 million people were affected but luckily for them, the power was restored in the next 1-2 hours.

North Central U.S. (1998)

On June 25th, 1998, a frightening lightning storm in Minnesota struck a power line which caused a transmission failure. A second strike which followed caused a disconnection between the transmission lines. Eventually, the northern Midwest got separated from the Eastern grid. The residents of the upper Midwest, Central Canada had to go without power for over 19 hours.