What happened
While the aircraft was skimming a broken layer of clouds with approximately 2,000 feet of vertical buildup, it encountered a moderate burst of turbulence lasting about one second. The captain had issued a landing preparation announcement approximately six minutes prior to the event. According to the captain, there were no radar indications or visual observations suggesting anything more than light turbulence.
Prior to the impact, the captain instructed the flight attendants to secure the cabin and take their seats due to potential turbulence. During the process of cleaning up the cabin, the turbulence became severe. The number one flight attendant reported that the number two flight attendant fell onto her ankle during the event.
Findings
Upon arrival at the gate, emergency personnel applied a splint to the injured flight attendant's ankle. She was subsequently transported to a hospital, where medical staff confirmed she had sustained 1 broken ankle.