The pilot reported that he made a normal approach to the runway with a "light head wind" in his experimental light sport, weight-shift trike. During the landing flare, when the trike was about 5 to 10 feet off the ground, "an unexpected gust or ground turbulence threw [the trike] sharp right off the runway." The pilot was unable to straighten the trike, which then impacted the ground, resulting in substantial damage to the fuselage. The pilot reported no preexisting mechanical anomalies with the trike. The winds were reported as calm at an airport 8 miles to the north at the time of the accident.