What happened
The flight crew had received prior warnings regarding expected severe turbulence while descending into the Denver area. In response to these warnings, the 'Fasten Seat Belts' sign was activated, and flight attendants were directed to ensure all passengers were seated and belted.
During this period, an elderly passenger stood up to walk toward the aft lavatory. As a flight attendant attempted to occupy a jump seat to secure themselves, the aircraft encountered light turbulence. Before the passenger and crew member could properly fasten their seat belts, the aircraft entered a zone of severe turbulence.
The sudden movement caused the passenger and one flight attendant to be thrown about the cabin, resulting in one serious injury and one minor injury. Additionally, another flight attendant and a second passenger sustained minor injuries during the event.