Depth is part of it. Superior is deeper but Ontario is further south. Erie is furthest south but is shallowest.
In the rooms of her ice-water mansion
Old Michigan steams like a young man's dreams
The islands and bays are for sportsmen
And farther below, Lake Ontario
Takes in what Lake Erie can send her
And the iron boats go as the mariners all know
With the gales of November remembered
Sorry, That is Obligatory, it my favorite song of all time though. The Wreck of the Edmund Fitzgerald- http://www.youtube.com/watch?v=hgI8bta-7aw&feature=kp