Hoover dam explosion: here’s what just happened at the iconic landmark

A transformer blew earlier today at the Hoover Dam, which sits on the Arizona-Nevada border. In a tweet, the U.S. Bureau of Reclamation, which operates the dam, reported that "the A5 transformer" caught fire at approximately 10 a.m. local time. No injuries were reported, and the power supply was apparently uninterrupted.

At approx. 10 a.m. PDT, the A5 transformer at Hoover Dam caught fire & was extinguished by @usbr/Hoover fire brigade at approx. 10:30am PDT. There are no injuries to visitors/employees. There is no risk to the power grid. Power is still being generated from the powerhouse. 1/2? pic.twitter.com/SYbXZHcZhA

— Bureau of Reclamation (@usbr) July 19, 2022

Videos posted to social media after the fire broke out appeared to show the immediate aftermath of a small explosion. A Twitter account under the name of Nashville-based realtor Kristy Hariston was among the first to share a short video showing the plume of black smoke rising from a small fire on a platform near the surface of Lake Mead. That video was watched more than 1 million times within the first hour after it was posted.

A few minutes later, an unverified account that apparently belongs to the city government of Boulder, Nevada, reported that its fire department was en route to the dam. A follow-up tweet reported that the fire was extinguished before city firefighters arrived at the scene. 

the fire was extinguished before Boulder City Fire Department arrived on scene. Bureau of Reclamation/ Hoover Dam will be handling any additional questions.

— CityofBoulderCityNV (@BoulderCityNev) July 19, 2022

The Hoover Dam was built by the federal government during the Great Depression. It generates more than three terawatt-hours per year and impounds Lake Mead, the largest-capacity reservoir in the country. The hydroelectric dam provides energy to millions of customers in the western United States. 

Transformers are an important technology that sit between electrical circuits and change the voltage without affecting the frequency of an electrical current.