Don,

I may have done some dock repairs this summer up in your neck of the woods - Hay Lake just outside of the eastern border of Algonquin Park. (My kids loved it up there!)

My uncle's docks are built like brick houses to survive the tough ice conditions. Unfortunately, there were heavy winds this spring right when the ice started to break up and it tore up one of the docks pretty badly.

Ice dynamics are pretty interesting. My uncle told me a story from one brutal winter in the 60's when he went up to work on the cabin and hunt. (He may have been a little younger and a little "less wise" at that point.) He went out on the ice with his chainsaw to get down to freshwater since they were going to be there a full week. He had cut down a hole so deep that only his hat was poking out while he was working. Some guys then zipped by on snowmobiles and apparently never saw him.

One of the old-timers went to check on my uncle to see what he was up to. At that point he was at least 5 1/2' down and was still in solid ice - even though he was almost to the bottom of the lake. The old-timer stroked his beard and told him the problem was he was in the "narrows". It was a narrow section of lake that connected two deeper lakes and was only 6' deep max, even though it was 400' wide.

The old timer said that the good ice fishing spots in the narrows froze solid by the end of winter. He suggested going over to the deep water on the other side of the point. My uncle did that and said he reached water under about 24" of ice (to his recollection).

Obviously, temperature matters on ice formation. However, there are many other factors that can influence ice formation.