A hot air balloon crash-landed near Denver Sunday morning, CNN reports. The crash occurred at Chatfield State Park, where police believe a strong gust of wind led the balloon to topple out of the air. Of the passengers, three people were taken to the hospital with serious but non-fatal injuries while another three remained stable. According to the Colorado Parks and Wildlife—Northeast Region, first responders gathered in an open field to respond to the balloon, which landed near the state park’s gravel ponds.