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A tower crane fell from the roof of a Seattle building on Saturday, landing on six cars and killing four people, including two workers who were in the crane. Four other people were reportedly injured, none of whom suffered life-threatening injuries.

The crane was on top of a South Lake Union building and was involved in construction with Seattle's new Google campus.

Washington state's Department of Labor and Industries is investigating the cause of the accident, though several witnesses and the National Weather Service reported a storm squall with high-powered winds moving through the area at the time. One witness called the scene "terrifying," while another described the crash as sounding like thunder.

The incident was the first fatal tower crane collapse in the Seattle area in more than a dozen years. It occurred during what The Seattle Times writes is a period of remarkable growth for the city, which has seen a heavy amount of construction as a result.

Read more at The Seattle Times.