The pilot reported that during landing the wind sock at the airport indicated that the wind was variable, about 5 knots, and predominately favored runway 1. According to the FAA airport facility directory, runway 01/19 was 1,850 feet long, and soft gravel. However, 1,000 feet of northern portion of the runway was closed indefinitely. The pilot recalled that about 500 feet down the 1,850 foot runway, and just before touchdown the airplane encountered, "a pretty rapid shift in the winds in both direction and velocity." He reported that the airplane touched down momentarily, and then went airborne again. After the second touchdown, the speed did not decline as expected, and although the airplane did start to slow as it got a better grip on the gravel (which was wet from rain that had occurred earlier), he ran out of runway. He reported that the airplane overran the runway at a groundspeed of about 10 knots, went down a small embankment, had a propeller strike and the airplane sustained substantial damage when the left wing struck a post. The pilot reported that there were no mechanical malfunctions or anomalies during the flight that would have prevented normal flight operations. The pilot reported that he considered going around, but due to the wind and terrain rejected the idea.