The pilot reported that while on final approach to runway 36, he observed that the wind was gusty and out of the west. He stated that his tailwheel airplane touched down normally on the grass runway and during the rollout on the main wheels, the tail of the airplane pitched up suddenly. The pilot moved the elevator to the full down aft position; however, the nose of the airplane continued to pitch forward. The airplane flipped over and came to rest upside down. The right wing, vertical stabilizer, and rudder sustained substantial damage. The pilot reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation. The grass airstrip did not have weather reporting facilities; however, an airport about 7 nm southeast reported the wind to be 280° at 10 kts.