The pilot reported that he departed a private airfield earlier in the day, and, at the time he departed, the wind was from the north about 5 knots. About 3.5 hours later, he returned to the airfield, which has a north-south oriented runway. The pilot stated that, due to terrain obstructions, landing to the north was “unadvisable.” The pilot added that the wind socks at the airfield indicated a slightly northern wind, light and variable, with no gusts. The pilot stated that he flew three passes to assess the wind, then made his approach and landed to the south. He added that, throughout the landing roll, the airplane was not affected by the wind; however, when the airplane was traveling about 5 knots ground speed, a crosswind gust blew the airplane off track, lifted the tail, and the airplane flipped over onto its back. The airplane sustained substantial damage to its vertical stabilizer and canopy. The pilot reported that there were no airplane malfunctions that contributed to the cause of the accident. About an hour before the accident, the automated weather reporting station located about 14 miles west of the airfield reported wind from 040 degrees at 15 knots gusting to 19 knots. About 5 minutes after the accident, the automated weather reporting station located about 19 miles southwest of the airfield reported wind from 050 degrees at 11 knots gusting to 17 knots.