The pilot was back taxiing for departure on Runway 18 (2700 feet by 60 feet, dry/asphalt. The pilot stated that, as he taxied near the area adjacent to the hangers on the east side of the runway, the aircraft turned abruptly to the right. The pilot applied full left rudder and the aircraft nosed over and came to rest in an inverted attitude. A weather report, for a reporting station located 25 miles and 28 degrees magnetic from the accident site, reported winds from 100 degrees magnetic at 16 knots gusting to 23 knots.