On May 5, 2007, about 1030 Pacific daylight time, a Cessna 150M, N45316, veered off the runway and collided with a ditch during a crosswind landing at Sonoma Skypark Airport, Sonoma, California (OQ9). Sonoma Skypark Flight School was operating the airplane under the provisions of 14 CFR Part 91. The private pilot, the sole occupant, sustained minor injuries; the airplane sustained substantial damage. The local area personal flight departed Napa County Airport, Napa, California (APC), about 1010. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot stated in a written report that he configured the airplane for a straight in approach to runway 26. After touchdown, the airplane veered to the left and departed the runway. The airplane continued through an adjacent field and collided with a ditch. The airplane sustained substantial damage, including a buckled firewall and a bent left wing spar. The closest official weather observation station was APC, which was 8 nautical miles east of the accident site. The elevation of the weather observation station was 35 feet msl. An aviation routine weather report (METAR) for APC was issued at 0954. It stated: winds from 360 degrees at 19 knots gusting to 28 knots; visibility 10 miles; skies 25,000 feet scattered; temperature 25 degrees Celsius; dew point 2 degrees Celsius; altimeter 30.04 inHg. The pilot reported no preimpact mechanical malfunctions or failures with the airframe or engine.