On August 17, 2016, about 1215 central daylight time, United Airlines flight 1945, a Boeing 737-924, N37408, encountered moderate turbulence near Waco, Texas, while on the approach to land at George Bush Intercontinental Airport (KIAH), Houston, Texas. Of the 142 passengers and crew onboard, one flight attendant received a serious injury. The airplane was not damaged. The flight was operating under the provision of 14 CFR Part 121 as a scheduled domestic passenger flight from Seattle-Takoma International Airport (KSEA), Seattle, Washington. The captain was the pilot monitoring, and the first officer the pilot flying. About 40 minutes from landing, the captain called the cabin and asked the flight attendants to prepare the cabin early and be seated because he anticipated light chop/turbulence. As the flight was descending from FL330 feet to FL240 on the GUSHR2 RNAV arrival the airplane and was in and out of cumulus and stratus clouds. The seatbelt sign was illuminated, and the weather radar was on but there were no indications of turbulence depicted in front of the airplane, though the crew could see that the weather was building rather than dissipating with scattered cumulus clouds all around. As the flight entered one small cloud, the airplane encountered a very brief duration of moderate turbulence. The autopilot did not disengage. Shortly after, they received a call from the cabin informing them that one of the flight attendants had been injured. At the time of the turbulence, the flight attendants (FA) were finishing their passenger compliance checks and securing the galleys. One of the aft FAs was in the process of securing the final latches in the galley when she was tossed about the galley, seriously injuring her right ankle. The other FAs assisted with stabilizing her and the flight landed without further incident. Paramedics met the airplane at the gate and the FA was transported to the hospital where she was diagnosed with a broken ankle.