Ice is endlessly fascinating; its various forms are a frequent topic for this blog in the winter.
As the air temperature now ranges between -15C and -10C, ice is making its appearance along the shoreline. It forms where the water is shallow, flow is minimal, and waves aren’t disruptive. Initially, it is frazil: individual crystals floating freely. These proliferate and consolidate to form skim ice, which now covers the water surface, but lacks strength. These are stages in the formation of the border ice that clings to the shoreline.
Frazil ice has consolidated to form some chaotic-looking skim ice.
Elsewhere, border ice has formed so slowly that it contains few bubbles and so is almost transparent. It looks dark because we are looking through it into the water below. The white crystals are frost growing atop the border ice.
The ice crystals in the top photo show a conspicuous preferred orientation with long elements left-right in the image. This indicates that forces at the waters surface were not equal in all directions. When I mentioned this to Alistair, he suggested that there may have been a very gentle swell impinging on the shore. This would tend to orient the free-floating frazil with their long dimension parallel to the shore, accounting for the observed directed pattern. Neat!
Too fun. Frazil, skim ice. And I see ice crystals’ facets flashing suspended at every visible level of air these days. And most extravagant fronds formed on motorcars by night’s cold and beauteous mathematics.