The pilot reported that, while on short final, about 50 feet above the ground, the airplane rolled about 30º to the left. He applied full right aileron and leveled the airplane about a couple feet above the ground, but the airplane descended on to the runway, exited the runway to the left, and impacted terrain. The airplane sustained substantial damage to the both wings and fuselage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The automated weather observation station located on an airport about 5 NM away reported that, about 15 minutes before the accident, the wind was from 050° at 16 knots. The pilot reported the wind was 050º at 10 knots, gusting up to 20 knots. The weight-shift control aircraft landed on runway 25.