The picture is of a hang glider (person unknown) landing in Beaver Pond, in Telluride, Colorado. The exact date is unknown, but probably from the 1970's. Here is an email, provide by Craig Muhonen, about an article written by John Heiney, about Telluride Hang Gliding's 25th year festival: "Rainy, But Good Telluride Hang Gliding Festival’s 25th Year © John Heiney The atmosphere of the 1998 flying season has been somewhat overbearing...