On October 12, 2018, about 0916 MDT, Frontier Airlines flight 190, an Airbus A319, N926FR, encountered turbulence while climbing through 24,000 feet after departure from Denver International Airport (DEN), Denver, Colorado. Of the 24 passengers and crew onboard, one flight attendant received serious injuries. The airplane was not damaged. The regularly scheduled passenger flight was operating under 14 Code of Federal Regulations Part 121 from DEN to Austin Bergstrom International Airport (AUS), Austin, Texas. According to the flight crew, the flight encountered only intermittent light turbulence during the initial climb. However, as the airplane was climbing through flight level 240, they encountered continuous moderate turbulence. The airplane began to accelerate rapidly so the captain disconnected the autopilot and increased the climb. There was no convective activity in the area and no reports of any turbulence from other airplanes. At the time of the turbulence encounter, two flight attendants in the aft galley were preparing for cabin service. Initially, the turbulence was light, however, when flight attendants felt the intensity increasing, they moved to get into their jump seats. Before they could get in their seats, they were both thrown into the air and then onto the floor. One flight attendant injured her ankle and the other injured her knee. The captain called back to the cabin and was told that one of the flight attendants was seriously injured. He declared a medical emergency and requested paramedics meet the flight on arrival. After landing, one flight attendant was transported to a local hospital where she was diagnosed with a broken ankle.