At the conclusion of a local formation flight, the flight of weight-shift-control aircraft returned to their home airport and entered the traffic pattern. During the landing flare, the accident pilot encountered the "prop wash" of the preceding aircraft, which resulted in his aircraft entering an uncommanded right bank. The pilot attempted to counteract the turn by applying a left banking control input, but the left main landing gear and nose landing gear impacted the ground, and further aggravated the turn. The nose landing gear then collapsed and dug into the soft turf runway, and the aircraft overturned to the right, where it came to rest on its right side. Examination of the wreckage by a Federal Aviation Administration inspector revealed that the airframe had been substantially damaged during the accident. The pilot reported that there were no mechanical malfunctions or failures or the aircraft that would have precluded normal operation, and when asked how the accident might have been prevented, the pilot stated, "…I could have performed (possibly) a go-around."