Even if it is not an ice swim, on the way to and from water look out for the different forms that ice can take. Having lived in houses with central heating, fern frost was something I’d heard of but never seen. Spending a winter night in an old lighthouse on the Hudson River I woke up to see delicate patterns of fern frost inside a window that was an oldfashioned single pane of glass. Fern frost happens when water goes from gaseous to solid, skipping out the liquid phase of cooling. Particles of dust or dirt on the glass serve as nucleation points, and their haphazard distribution gives fern frost its characteristic abstract shape.
In contrast needle ice forms orderly columns. It forms when the air is freezing but the ground is not. Capillary action draws water to the surface where it freezes. I don’t see it the sandy soil around my house, but I do see it in woodlands. It tends to form in soils that are rich in organic matter, and is often found on stream banks.