The article
here.

When Gerry Uchytil and a friend heard about a hang-gliding club
starting up in southern California in the early '70s, they sent for a kit and
built a glider. Uchytil has been flying ever since, through the sport's heyday
in the '70s and '80s, when there were about 200 hang gliders in the Twin Cities,
and Uchytil was part of the Skyline Skydogs Club near Duluth. Now, Uchytil
estimates there are five or six hang gliders left in the Twin Cities. As a
teacher, he does most of his flying in the summer, but conditions are best in
spring, when the warm daytime temps following cooler nights cause the air to
rise.