The pilot stated that during an approach to landing in gusty crosswind conditions, the airplane encountered turbulence about ten feet above the runway and suddenly lost altitude. The airplane landed hard, and collapsed the nose landing gear, then exited the right side of the runway and collapsed the main landing gear. The airplane sustained substantial damage to the left wing and fuselage. The pilot reported no preimpact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation. A review of local weather data indicated that there was low level wind shear associated with high based convective activity approximately five miles north of the airport. There were several pilot reports in the area indicating moderate turbulence below 10,000 feet. Additionally, two pilot reports for moderate turbulence below 2,000 feet and low level wind shear were made within an hour of the accident. The National Weather Service issued an Airman's Meteorological Advisory, current at the time of the accident, for turbulence below 10,000 feet.