According to the pilot of the tailwheel-equipped airplane, he took off from grassy, wet, down sloping terrain. He recalled that he walked the area of intended takeoff and found no obstacles that would prevented a safe takeoff. However, he reported that during the takeoff roll, he kept the airplane tailwheel off of the ground, while rolling down slope, and the airplane main landing gear wheels rolled over a patch of mud creating a pivot point, and the airplane nosed over. The airplane sustained substantial damage to the vertical stabilizer, rudder, and wing struts.
The pilot reported that there were not any mechanical malfunctions or anomalies with any portion of the airplane, prior to the takeoff roll that would have precluded normal flight operations.