A number of years ago, my cousin Paul Chamberlain and I hiked along the Carp River to Lake Superior. We found that the river was frigid. It made Lake Superior feel warm.<br /><br />For those not initiated in our Great Lakes, just let me say that Lake Superior is said to come in two temperatures -- the temperature of liquid ice, and the temperature of solid ice.<br /><br />(To be fair, some of the bays along the north coast of Michigan's Upper Peninsula are plenty warm for swimming.)<br /><br />I had assumed that the lake was every bit as cold, but I was later told that Lake Of the Clouds is warm enough to be swimmable. When we hiked down there just recently, I found that to be true.<br /><br />According to the map, the Carp River goes underground for a space. That would explain why the river is so cold.