The pilot of a tailwheel equipped airplane reported that after performing a wheel landing, the tailwheel settled onto the runway. Shortly after, the airplane encountered a strong gust of wind or dust devil, which turned the airplane about 90° to the left. Subsequently, the airplane exited the left side of the runway, traveled down an embankment, and both main landing gear collapsed before the airplane came to rest upright. The airplane sustained substantial damage to the left wing. The pilot reported there were no preimpact mechanical malfunctions or failures with the airframe or the engine that would have precluded normal operation. At the time of the accident, the pilot was landing the airplane on runway 31 with wind from 270° at 10 knots, gusting to 15 knots. One witness characterized the wind as a spiraling wind with extreme lift.