Why am I showing you a photo of the snow on my back deck? I just want to point something out. That big pile of snow out there has been shrinking, quite a lot, but you can see the deck isn't wet. I took the first photo looking down just now. The second photo was from yesterday.

Big difference!

In the spring, we normally think of our snow as melting away. That is when it goes from a solid to a liquid state. And, yes, definitely it does that, but it's still too cold to melt right now. What's happening out there? I forgot about this other transition...

Sublimation: To be transformed directly from the solid to the gaseous state or from the gaseous to the solid state without becoming a liquid.

And there is the before photo for reference. These very cold dry days are perfect for sublimation. It's still below freezing (0 C or 32°F) but warm enough to produce a gas. You are familiar with evaporation, since it is similar, occurring when a liquid transforms to a gas and I'm certain you ran into all of these words before, probably in some long ago science class. Sublimation or the act of subliming, just isn't heard so often and it's kind of interesting to see an example. I also like it better than melting as you might imagine we end up with huge puddles of water.

Close up, the snow is no longer powdery and it's more crystal-like. With some melting, the bank of snow becomes smaller and heavier, sometimes pure ice on the bottom and dirtier too.

References

Sublimation

Images

Photos from the Canon SX620 HS of @kansuze.

@kansuze