The pilot was landing to the east on the turf runway for the third time; the previous two landings were uneventful. During the landing roll, the airplane rolled over the bumpy turf surface, the empennage came up, and the airplane’s nose moved down. The pilot attempted to correct the nose down condition with an elevator input. When the airplane traveled over the paved taxiway that intersected the runway, the pilot opined that it exacerbated the situation. The airplane subsequently nosed over and came to rest inverted. The fuselage, vertical stabilizer, and rudder sustained substantial damage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The pilot stated that taxiway that crossed the runway was raised relative to the runway surface; however, he did not feel that the difference was the reason for the nose over. The airport facility directory noted that the turf surface was in fair condition, the runway was not maintained in winter, and that a taxiway intersected the turf runway at midfield.