For the first few years in which I would excitedly go out on frosty mornings to photograph ice formations, I never paid any attention to frost on car bodies. Sometimes I would notice something on our car window, but that was basically it – I was essentially blind to ice in places where I didn’t expect to see anything interesting. Then one day, while returning from an area that often had fascinating puddles and ground ice, I walked next to a black car with the most stunning display of frost that I had ever seen. The car was completely covered roof, hood, and trunk with a thick, large, curvy white pattern of ice made distinct by the background of black underneath.


I spent the next hour or so taking pictures, returning home once to get another camera when my roll of film ran out. Though I understood roughly the processes involved, the initial freezing of a thin layer of water, making curvy ice patterns, followed by vapor depositing onto the frozen parts as hoar, making the ice white, there were other puzzling things that kept me entertained. However, the most puzzling thing of all was the fact that people would walk right by without even slowing down. Here was a strange and rare sight: strange because of the hastily dressed man (myself) leaning over a parked car with a tripod snapping pictures, and a rare yet striking display of curving frost in full view, and yet they paid me nor my prize no mind. It was as if I was the only person who could see the pattern.

The reverse thing happened to me just a few days ago. We had wet weather one day followed by a cold, clear night – perfect conditions for good hoary film frost. And indeed, many cars in our parking lot had beautiful curvy film-frost. I walked around, looking specifically for black cars, which show the most contrast to the white hoar, and photographed some on one car, but somehow overlooked the most amazing one of all: a speckled-seaweed-like pattern that I've seen only once before (see the Dec. 1 posting).


Even though the above was on a black car in a region I checked, I still missed it. But luckily, my neighbor caught it and emailed a few photos. In the image, some of the trails seem to cross over each other, but closer inspection instead suggests a coincidental merging of two trails on one side with a forking off on the other side.


As in the previous case when I saw such a pattern, the frost had formed on glass, with a completely different pattern on the adjoining metal surfaces. The same happened here, with the rear trunk and spoiler surfaces having a different type of curvy film-frost:


However, the hood of the car showed a similar type pattern, a pattern I called ‘striped-tail’ frost (e.g., Jan. 31, 2010 posting). See the red arrows in the image below.


Elsewhere, I have also seen a transitional pattern, with wider ‘tails’ blending in more with the surroundings.

-JN

Two other cases of speckled-seaweed frost from elsewhere:
1) http://www.flickr.com/photos/addieplum/3548833/in/photostream/
and
2) http://www.flickr.com/photos/pwiwe/2400648741/in/pool-374031@N22/