up in the mountains rather often, but we get that kind of cold often too. What I have seen here that I have never seen anywhere else - and I have lived in northern IL and southern WI during several cold winters - are the sun dogs that are not only a complete circle with cardinal points very well defined but also a mirror image of the circle appearing above the upper cardinal point. Kind of looks like a Taurus glyph made out of rainbow parts.
This last Nov. I saw one that really amazed me though, never seen this before, a double ring around the sun (like a double rainbow) with both rings having mirror images above them all at once. That was amazing, and hard to capture on a camera. Wonder if I'll ever see something like that again.
But they sure are neat to see, one of the small but pleasant trade-offs of extreme cold.
The pictures are cool, thanks for posting!