Flight Details
Before takeoff, the flight crew received weather information indicating the possibility of thunderstorms and turbulence along their flight path. As the aircraft climbed through 24,000 feet, the crew diverted around a rain shower that appeared benign.
Turbulence Encounter
While passing the rain shower, the aircraft encountered three jolts of moderate to severe turbulence. At the time, all three flight attendants were preparing to serve the cabin. One flight attendant sustained serious injuries during the encounter.
Operator Procedures
The operator's flight manual states that the flight crew should instruct the cabin crew to secure the cabin and be seated before an encounter with turbulence.