The moment I saw this snowflake in my viewfinder I got excited. That vibrant splash of colour captivated me, and it’s quite rare to find such an elaborate flowing display of vibrancy in a snowflake! View large!
Small plates are typically the place where we see colours derived from thin film interference, and this one qualifies at just over 1mm in diameter. The colourful features are a bit perplexing though, reminiscent of stress patterns seen through birefringence in plastics. There’s some propeller-hat words in the previous two sentences, but it boils down to this: it’s a strange crystal!
It’s helpful to remember how a snowflake grows – from the center outward. It’s easy to see this as pools of colour that spill in towards the center, but the actual growth is opposite. Small bubbles / cavities began to form in the center of the snowflake, and their exact position wavers due to shifts in wind direction and incredibly small changes in humidity. This can cause the cavities to meander and create an organic appearance until things stabilize and three larger cavities form.
The thickness of these cavities may vary, or at the very least the thickness of the surface ice is changing in thickness. This creates an interference rainbow effect that’s very commonly seen in soap bubbles, as gravity pulls more of the bubble to the bottom and creates swirling patterns of colour. It’s hard to say if the bubbles are getting thinner or of it’s an effect of inward crystal growth creating the smooth colour shift. This is a rare thing to see in snowflakes!
This was also the only snowflake in the entire snowfall that showed colourful features. Like winning the lottery, I found it in front of my camera to do the same technical process I have done for many hundreds of snowflakes before, yet I get something new and interesting to share with the world. Nature works in mysterious ways, and it makes snowflake photography rather addicting!
If you’d like to know my entire photographic workflow that I use to create this image (and every one of my snowflake photographs), you’ll want to flip through the pages of Sky Crystals: https://www.skycrystals.ca/book/ - the book also covers all of the science of how snowflakes form and why we can find such vibrant colours created within them. For your curiosity, here is a few pages that describe the “thin film interference” phenomenon we’re enjoying in this colourful snowflake: http://skycrystals.ca/img/optical-interference-pages.jpg - the book is a great winter companion to any photographer or naturalist!
Many more snowflake still to come!