The pilot was landing the Cessna 190 on runway 13, a 2,800-foot-long, 50-foot-wide, concrete runway. During the landing roll, the airplane encountered a wind gust from the left, and drifted off the right side of the runway, where it subsequently nosed over into a drainage ditch. Examination of the airplane by a Federal Aviation Administration inspector did not reveal any mechanical malfunctions, nor did the pilot report any. Winds reported at an airport located about 10 miles southwest of the accident site, about the time of the accident, were from 070 degrees, at 15 knots. In addition, thunderstorm activity was reported in the local area.