Incident Overview
Two flight attendants sustained serious injuries when the airplane encountered severe turbulence during its descent for landing. The turbulence was likely the result of strong easterly winds interacting with the rough terrain in the area, a phenomenon known as mechanical turbulence.
Turbulence Intensity
Data from the flight data recorder indicated that the airplane experienced vertical accelerations ranging from +0.4 G to +1.9 G, a total change of 1.5 G, which corresponds to the definition of severe turbulence.
Weather Information
The National Weather Service had forecast severe turbulence in Significant Meteorological Advisory (SIGMET) Victor 2, which was issued before the flight departed. However, a weather company that provides information to the operator did not forecast severe turbulence for the area. Although the content of SIGMET Victor 2 was available to the flight's dispatcher, this information was not provided to the flight crew.
Injuries
At the time of the turbulence encounter, the two flight attendants were standing and completing final cabin duties in preparation for landing. They were knocked to the floor during the event, resulting in serious injuries.