Incident Details
While cruising at FL290, a pilot was navigating around isolated thunderstorms. A Flight Watch advisory notified the pilot of a SIGMET indicating thunderstorm formation between Colorado and New Mexico. Acting on Flight Watch's suggestion, the pilot turned toward an alternate airport. However, rapidly developing cells forced continuous heading changes, and fuel became insufficient to reach that alternate, prompting a diversion to another alternate airport.
Weather Conditions
All anti-ice equipment was activated. During descent through clouds, mixed icing began accumulating rapidly on the aircraft. As the pilot executed a 180-degree turn to exit the icing conditions, the aircraft encountered severe downdrafts.
Aircraft Actions
The pilot declared an emergency and successfully landed at the chosen alternate airport in visual meteorological conditions without further incident.
Postflight Findings
Postaccident examination revealed that the inboard panels of both bonded wings were wrinkled. The damage necessitated the replacement of the entire wing assembly.