Another factor that may have played a part is Low Level Flying in moderate winds (gusts to 15knots) while keeping eyes on a fixed ground point and turning around that point. In this case he was down wind before the turn, possibly using ground speed as his reference. Experienced Alaskan Pilot, Shaun Lunt, also caught out by this scenario which ended in tragedy while circling a whale carcass in his Super Cub on a windy day in Alaska around 10years ago.