It's massive ... and cold AF. Average temp 1' below the surface in August is 52 degrees.
The first year I move to the Twin Cities was 1988, and Duluth was one of the terminals that reported to me. Made it up there for their St. Patricks Day celebration (a very good time) and the town was abuzz talking about a group of ice fisherman that walked out onto the ice with their dog to enjoy a night of beer drinking, camaraderie and perhaps catch a fish or two.
Well ... the wind changed direction overnight and the entire ice shelf broke loose from shore and drifted out into the lake. When the sun came up, those guys realized they were basically sitting on an iceberg in the middle of Lake Superior. The first guy out of the ice hut to take a piss probably also shit himself when he realized their predicament.
"Uhhhh ... guys, you're gonna want to step out here and take a look at this".
Remember, this was 1988 and cell phones were not yet ubiquitous. We also had a good laugh imagining the telephone tree amongst the wives:
"Linda, have you looked out at the lake this morning?"
"No, why?"
"Well ... the ice is gone, and so are our husbands. The wind must have blown them out to sea!"
"Do you think we should call anyone?"
"Maybe ... eventually ... probably. I mean, what would YOU spend the insurance money on?"
Well, someone did call and the National Guard flew out in helicopters to locate and rescue them. IIRC, they had a hard time with the dog who attempted to evade capture as he probably (correctly) assumed they were going to cook and eat him.