The pilot of a tailwheel equipped airplane reported that he used a "standard crosswind technique" during the final approach, but just before touchdown the nose of the airplane shifted 25 degrees to the left of the runway centerline. After touchdown, the pilot attempted to correct with the rudder and ailerons, but the airplane veered to the left and exited the runway surface. During the runway excursion the right main landing gear collapsed and the right wing impacted the terrain. The right wing sustained substantial damage. The pilot stated there were no mechanical malfunctions or failures with the airplane that would have precluded normal operation. METEROLOGICAL INFORMATION The pilot reported that there was a crosswind during the final approach, and the wind shifted to a quartering tailwind during the touchdown. About the time of the accident at the airport, an automated weather observing system reported the wind at 020 degrees true at 5 knots, which resulted in a quartering tailwind.