To all of my friends, family and colleagues in the United States of America – have an excellent Independence Day! I chose to dig through my unedited snowflakes from last winter to find this gem, almost like a frozen firework. View large!
Originally photographed February 15th of this year, this was one of many snowflakes that I just couldn’t edit over the winter months for lack of time. It has a few unusual features in the center, but it’s largely what many people would consider a “classic” snowflake for a classic celebration.
The center of this crystal is interesting on three levels. If we look at the very center, you’ll notice that this crystal began as a column that grew plate-like crystals from each side – the evidence for this is the tiny hexagon shape seen through the ice. This little hexagon is a smaller plate on the opposite side of the crystal that stayed small while the other side grew, probably because it was facing the direction of incoming water vapour. That scenario is common; I’ve seen many dozens of snowflakes with similar features. What sets this snowflake apart is that it is also a “split plate”.
A split plate is when two plates complete for water vapour and some corners on one side “win”, while the remaining corners grow out from the other plate. As soon as one corner of a plate is larger than its parallel competition, the battle is over – the larger footprint gathers more water vapour and it grows exponentially. This in itself is also very common. What I don’t think I’ve ever seen before is a “jewel-like” plate on one side and a split plate on the other, because it would require three plates at the origin and a column would typically only have two ends.
Typically, of course. On rare occasions I have seen plate-like growths start to form in the center of a column, sometimes due to collisions with super-cooled water droplets that freeze on impact and create a new nucleation point. Here’s an example of this: https://www.flickr.com/photos/donkom/11499384696/ - we also see small dark circles on the surface of today’s snowflake that indicate collisions with these same droplets (called “rime” when they accumulate in greater numbers).
A secondary plate may have formed to make this little snowflake extra confusing, but the magic for me is that it remains balanced. The beginnings may have been unusual and somewhat asymmetric, but the final snowflake feels like there is equal weight distributed on each branch. They fit together nicely, even though the branches are certainly not symmetrical. A thing of beauty no matter how you look at it!
Notice how I kept politics out of this write-up? I’d like to keep it that way in the comments, even though the word “snowflake” has taken on political meanings recently. Let’s just celebrate a great historical event and enjoy a fun macro photograph. Cheers to you, USA. Happy 241st Birthday!