What happened
Prior to the incident, the pilot contacted Flight Service Station (FSS) at 16:15 to request a weather briefing and to file an IFR flight plan. During this briefing, the pilot was informed of intensifying thunderstorm activity moving east and southeast, spanning from Garden City, Kansas, to Raton, New Mexico, with additional activity noted in the Oklahoma panhandle.
At 17:50, while climbing to 21,000 feet, the pilot established contact with Albuquerque Center. Shortly thereafter, at 17:55, convective SIGMET 70C was issued, warning of isolated severe thunderstorms situated approximately 10 miles north and northeast of Las Vegas, New Mexico. This weather advisory was not communicated to the pilot by the air traffic controller.
At 18:23, radio contact with the aircraft was lost. The pilot had previously reported operating under Visual Meteorological Conditions (VMC) while approaching precipitation. During this encounter, the aircraft struck hail, which caused the windshield to fail. This structural failure resulted in the depressurization of the aircraft.