A deadly flash flood swept through Payson, Arizona on Saturday, July 15, killing at least nine people at a local swimming hole and leaving one man missing.

The incident occurred at the Cold Spring swimming hole, also called Water Wheel Falls. According to a press release from the Gila County Sheriff’s Office and a report from AZ Central, 14 people were caught in the flood waters. Nine victims were killed when a “40-foot-wide black wave” of rainwater came hurtling towards them, and one person, a 27-year-old named Hector Miguel Garnica, is still missing.

This footage shows a glimpse at the flash flood waters. The uploader, Scott Muller, wrote that he had filmed the video while with a volunteer group in the area. He said had never seen a flood of such magnitude before and did not know that people had died until he returned home that evening. Credit: Facebook/Scott Muller via Storyful