The weather the past week has been more typical of this time of year with temperatures hovering between +10 and -10 F. These are very good temperatures for crystal growth. The air at these temperatures is often very still and allows some intricate and delicate crystals to grow. Often these crystals are feathery in consistency and a gentle brush with a finger or a chance breeze will destroy them.
In the last several winters I’ve noticed patterns in crystal formation. There seem to be four main types. The first consist of delicate flat formations that resemble feathers both in shape and pattern. These are often the most delicate crystals growing on each other, hanging down from embankments, plants, or other structures; growing where moist air is escaping from below.
The second type of crystal consists of tube like structures and needle structures. Unless you look closely, they often look solid and round, but on closer inspection they most often are six sided and hollow. These also form where moist air escapes from below, often growing on the underside of suspended ice. These are much more rare than the first type.
The third type is perhaps the most common. This type consists of blades. Similar to the first type in shape, but less fragile. These often grow on the surface of snow and ice and seem to grow right out of the existing substrate.
They don’t seem to appear until it gets colder and I suspect are formed with the interaction of sunshine and cold air on the surface. These crystals also grow on trees, and any other surface, but always have a flat blade like appearance. The smaller of these are often clear while as they get larger they become opaque.
The fourth type and perhaps my favorite are the smaller six sided figures that often appear as perfectly formed tiny crystals on the surface of objects. These crystal formations can be either flat, or domed shaped. The best grow mushroom like with domed perfectly formed crystals appearing at the end of very delicate stalks. Although they can occasionally be found on wood and metal surfaces where the sun does not reach, I have had the most luck finding them on bare ice. On the bare ice they seem to form right from the ice and only when it is very cold.
I suspect that the very cold dry air draws moisture right out of the ice and allows these crystals to build atom by atom. Although rare, some of them can be extremely beautiful. Precursors to the six sided flat shapes are spears of ice that grow right from the surface. From these spears the six sided figures seem to sprout and in the best examples appear as mushrooms as described above. Because they are very small, require perfect conditions, and are easily destroyed, they are the hardest to find but my favorite.
Today’s crystals are mostly type one and four. I did photograph some type three crystals that are visible in the last few pictures here. I’ve also included one photo of type 2 crystals I found on Saturday since I did not find any today.
I was excited to find the type four crystals today. While the largest were easily photographed, as they get larger they run into each other and are not quite as nice.
All the type four crystals I found today were on ice that I cleared over a week ago to photograph bubbles. I cleared some more ice today to see if I can get more to grow. My favorites are the smaller individual crystals of which I found a few today. The difficulty is that the smaller and better ones are hard to capture and push the limits of my camera.
It was a great day to get out, the sun was up, the skies were clear, the crystals were plentiful. I hope these conditions continue.