I've noticed that some freeze dried puddles, have a series of circles on them, like a weather map and wondered what could cause them.

While walking in the Cairngorms, a path had muddy puddles one day, and was frozen the following day. Parts of the path were the mixture of ice, air and gravel pictured. The structures are noticeable, because they collapse when stood on. They are different to any normal frozen puddles, because they are not solid ice, nor are they a layer of ice with water or air beneath. The pictured piece measures about 65x65 mm.

On the surface of a puddle, I saw mutiple unbelivably straight lines. It's a windy day and there was lots of debris on the surface, creating numerous ripples. Did I witness a mundane event or is it statistically unlikely occurance?