The pilot, who was making a visual flight rules (VFR) approach to a 800-foot long remote airstrip, overflew the runway to observe the windsock. Because he observed the windsock hanging limp, he assumed that the winds around the runway were calm, and therefore continued his approach. About the time he reached the approach end of the uphill-sloping runway, the airplane encountered a strong tailwind gust which pushed it, "…too far up the strip to land." The pilot therefore executed a go-around, but his decision was "too late," and he was therefore unable to out-climb the terrain on the departure end of the runway. During the go-around sequence, the airplane's landing gear came in contact with low growing brush, and it flipped over onto its back. Ground witnesses told the pilot that all morning the winds had been variable in direction and had been changing rapidly from nearly calm to gusting as high as 20 miles per hour.