Lake Superior, fresh water body but why does it not freeze?

Question

I recently drove across canada and when passing by Lake Superior noticed it was not frozen along the coast. I was on the highway from Wawa to Sault Ste Marie. There were huge waves that you could surf, and it had a slight yellow tinge to it, much like you would see in salt water areas. If I hadn't known any better I would have thought it was salt water! Is there something that happens in areas that would cause this to happen? It was -52 at the time I was passing so I can't imagine why.. it wouldn't be frozen.

Answer 1

Lake Superior does freeze completely over, approximately once every 20 years. According to the Great Lakes Aquarium, Superior froze over nearly 100% in 1996, and before that, in 1979 and 1962.

It has to be a long, cold winter to do that, because Lake Superior is so large that wind and water movement breaks up any ice that forms during normal winters.

Answer 2

As water cools it tends to sink and be replaced by less dense warmer bottom water. This circulation keeps deep lakes ice free in most US climates. Lake Tahoe and Crater Lake do not freeze either. Lakes Erie and Ontario will partially or fully freeze each winter. Both these are shallow. Shallow lakes quickly reach temperature equilibrium and the convectional circulation ceases allowing them to freeze.

Answer 3

When water freezes, it has to give up a lot of energy. There's a lot of water in Lake Superior, so it manages to not freeze over. It would probably take months to freeze even if the Sun ceased to exist.

Answer 4

its a big lake