 The high-altitude bombing attacks using general-purpose bombs were observed to be ineffective by USAAF leaders due to high winds—later discovered to be the jet stream—which carried the bombs off target.Between May and September 1943, bombing trials were conducted on the Japanese Village set-piece target, located at the Dugway Proving Grounds.These trials demonstrated the effectiveness of incendiary bombs against wood-and-paper buildings, and resulted in Curtis LeMay ordering the bombers to change tactics to utilize these munitions against Japan.