Explosion, Fire Reported at Hoover Dam

A transformer exploded and caught fire at Hoover Dam in Nevada on July 19, according to local officials.

Bureau of Reclamation official Jacklynn L. Gould said that at about 10 a.m. local (Pacific) time, the A5 transformer at the site caught fire. The blaze was extinguished at about 10:30 a.m., according to Gould.

Gould said there were no injuries to visitors or employees. “There is no risk to the power grid and power is still being generated,” said Gould, who is the agency’s regional director for the Lower Colorado Basin.

The Bureau of Reclamation is a federal agency that oversees water management in the Western U.S. The Colorado River provides water to seven states in the West, including to Hoover Dam.

Firefighters work to extinguish a blaze that started when a transformer at Hoover Dam exploded on July 19, 2022. Source: U.S. Bureau of Reclamation

Visitors at the dam Tuesday morning reported hearing an explosion and seeing fire, along with a large plume of smoke, coming from the dam. Video of the smoke was posted on social media.

“Boulder City Fire Department is en route to an emergency call at Hoover Dam,” the City of Boulder (Nevada) said in a brief statement immediately after the incident, adding “No further information is available at this time.” City officials later, in a social media post, said “The fire was extinguished before Boulder City Fire Department arrived on scene. Bureau of Reclamation/ Hoover Dam will be handling any additional questions.”

Hoover Dam impounds Lake Mead, the largest reservoir in the U.S. The dam was built in the 1930s, providing thousands of construction jobs during the Great Depression.

At full capacity, the dam’s 17 turbines can produce nearly 2,100 MW of power, but low water levels due to extended regional drought have reduced the plant’s output by about one-third this year. Hoover Dam provides power for public and private utilities in Nevada, Arizona, and California, and is also major tourist attraction in the U.S. Southwest.

The 17 turbines include nine that are fed by the two towers on the Arizona side of the facility, and eight fed by the towers on the Nevada side. The original turbines at the site all were replaced between 1986 and 1993. More recent improvements include the rebuild of five turbines in the past 10 years. These rebuilt turbines, with a “wide head” design, operate more efficiently, and also perform better with a higher tolerance when hydraulic force falls. 

Darrell Proctor is a senior associate editor for POWER (@POWERmagazine).

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