Some of those looked like they formed on ponds.
and some like "crop circles"
The strangest thing I guess I saw, was one very frigid day I had to drive to Columbus Indiana. The snow there had frozen and blew into something called a snow roller, but I did not know what they were, and had never seen them. I though someone was going from farm to farm making these things, until i realized they were everywhere for miles and miles.
They are called snow rollers or other names, and forum cylinders, cones, and balls - some enormous.
Here is a pic I found online.