Michelle,
It's the Minnesota River School of Fine Arts just south of Minneapolis, in Burnsville Minnesota. It's run by Pat Jerde, who studied with Atelier Lack. She hosts many weekly classes as well as workshops.
http://websearch.cs.com/redir.adp?ap...2f&datasource=
Another excellent atelier is The Atelier Studio Program of Fine Art
http://www.theatelier.org/index.php in Minneapolis, MN, which was founded and run by Atelier Lack graduates, Dale Redpath and Cyd Wicker. It is one of the best four year atelier programs in the United States, but also hosts summer workshops.
Peggy