Awesome photo op. IMHO I would say it is an immature Great Grey or a Short Ear. Hard to tell without some more mature markings. It is a bit too far south to be a grey but the way birds move around its hard to say. But still young and already that bulky I have to go with the Great Grey Owl.
Keep fishing and keep smiling! Take care of one another folks! If you're lucky enough to be a Yooper, you're lucky enough.