Here we go! December 1st has arrived and I’ll be sharing a snowflake photograph every day up to Christmas, then we’ll see – likely every other day after that to make room for other projects. We’re in a bit of a warm spell right now but I still have hundreds of unedited images from previous years, and many of them are quite spectacular. View large!
I started working on this snowflake last night, knowing it would take longer than usual. There were bits of woolen fibers and shards of other snowflakes in front and behind it that were quite distracting, and it’s the reason why I didn’t add this one to last year’s series – there just wasn’t enough time. It’s worth the extra effort, because this is one beautifully strange snowflake.
Starting in the center, we have a rare feature: a thick “spine” on each branch that reaches almost all the way to the center, with a sharp 90-degree fall-off to the plates below. This is true of all branches except the top branch which is behaving normally – regular branching growth is easy to spot. The question is, why? I’ve only seen this spine-like design a few times before and it’s always somewhat baffling. As a snowflake grows outward, this would be the leading tip of growth, and only this tip maintains this level of thickness as it pushes out. The standard logic of “what sticks out the farthest, grows the fastest” applies, though dendrite growth usually happens at a faster speed. In this case, there are plenty of signs that it was growing slowly.
The easiest clue to the speed that this snowflake was growing is the very wide side-branches. If the crystal was gathering water vapour at a fast pace, you’d have narrow pointy branches. Lack of humidity can make a snowflake slow down, but so can temperatures warmer or colder than the optimum of -15C. Let’s assume that this snowflake had plenty of available building blocks (water vapour), but colder temperatures? This is a possible scenario for us to be in, though I don’t have a measurement for the cloud temperature where this snowflake was formed. Regardless, slow growth with plenty of water vapour is my best theory for these spines forming.
This snowflake does something else that is very rarely seen. On the five “spiney” branches, the detail on the snowflake flips sides. Most of this snowflake has all the surface relief features facing away from the camera on the backside of the snowflake, which is why they have less contrast. Notice the “spade” at the end of each branch where the final side-branches emerge from? Lots of contrast as the snowflake changed its mind and started growing surface features facing the camera (and none on the opposite side). This is commonly seen with split crystals, but quite unusual for the same branch to just flip-flop. Something changed, either in the way the snowflake was falling or maybe the spine diminished in size and eventually became flat with the rest of crystal allowing this shift to happen. It makes for a very interesting snowflake – and the top branch stays with relief only on the reverse.
All that in a single snowflake! There is a universe to discover here, both from simply enjoying the natural creation, but also in photographing them yourself – imagine having to choose from millions of snowflakes falling from the sky! My book on the topic, Sky Crystals, is now available as an eBook this winter for CAD$14.99, which is currently around USD$11.80. For a 304-page book giving exhaustive details on how I create these images, it’s worth every penny: https://www.skycrystals.ca/ebook/ - price goes up after Christmas!
You might be interested in a limited-edition pure silver coin that I designed for the Royal Canadian Mint for this winter: http://www.mint.ca/store/coins/coin-prod3040427 - selling fast, and last year’s sold out. :) If you’ve already got one, it would be great for you to write a review on the mint website!