The picture below is me on my Honda as a couple friends and I head out to Fish downriver. This was back in late December, so you can see that the sun is just rising, but it was about 11am when this picture was taken. It was also snowing, which you can sort of see in the picture. It made for quite an amazing ride. One of the most beautiful mornings I have ever experienced.
Being from California, I would imagine that when a river freezes it is flat, but that is not the case. It actually is fairly flat in a lot of places, while others are giant piles of ice sheets or bulges.
The pic below would be a bulge.
In the old days, people would have to make holes through ice this thick by hand in order to fish. Just another testament to how tough life was for Native people in the not so distant past. This is one reason it is very common still for people to fish and then put a stick in the hole for people to see so they could come and fish the same spot. This allows people to fish by just breaking a relatively thin layer of ice to open up an existing hole. It is common topic through the village of who has fished, when and where, and for the exact purpose of knowing where the fish are biting and where there are holes that have been recently opened up.
Just recently at the end of Feb. we were hit with a warm spell and the ice began to melt. In the pic below I am on the bank next to the village taking a picture of some people a little ways downriver who were crazy enough to go fish on this ice with Hondas. You can see all the water sitting on top, and it didn't seem very stable to me when I walked on it. When ice is freezing, it freezes somewhat evenly. However when it is melting, there is no telling where it will be thick and where it will be thin.